I don't know if this has already been done yet, but I was just curious to see which heroes or villains people like or play with the most! My vote goes to Tempest. What do you guys think?
Tempest for me as well. I love fighting against Gloomweaver. Zombie army? Crazy cultists? Dark God with ancient Relics? It's like I'm playing Games Workshop's HeroQuest all over again! With superheroes!
My heroes are in five tiers:
Top tier (AWESOME):
-Argent Adept
-Absolute Zero
-(promo) Fanatic
2nd tier (Yes please!):
-Nightmist
-Haka
-Tachyon
3rd tier (sure, why not!):
-Expatriette
-Mr Fixer
-Unity
4rd tier (hm, if we really need them and no one else wants to):
-Legacy
-Ra
-Tempest
5th `Bunker' tier:
-Bunker
Villain-wise, I'm not the greatest fan of no-target villains like Spite and Plaguerat, though they can be fun. I really like The Ennead, Akash'Bhuta, Apostate and Citizen Dawn.
My favourite hero is absolutely, definitely Nightmist :D. Heroes I enjoy playing to various degrees are Wraith, Ra, Tachyon, Ab' Zero, Legacy, erm, maybe Mr Fixer and Expatriette. Most of the others I'm not too fussed about, or am willing to play in certain circumstances (ie against certain villains) Not so keen on Bunker or Haka. Or Fanatic - I never seem to be able to do anything with her that doesn't involve killing myself because she's not good at healing.
I'm okay against any villain, but have to play certain heroes against some. For example, Nightmist versus Omnitron so I can Mistbind his deck whenever he's gonna flip to "draw a card at the end of the turn" mode and thereby have full control over his deck for the entire game (playing Astral Premonition when he's in the mode that only lets hiim draw one card on his turn). Played Tachyon versus Spite last night and that worked well - he couldn't punish me for using a power (once that drug came out) because I didn't have any, and then I used my Lightning Reflexes/Lightspeed Barrage chain-combo-thingy to deal 30 damage and obliterate him in a single turn (yes, I only had 10 Burst cards in my trash at that time :() :D. Stuff like Ra versus Voss/the Chairman is good 'cause of the AEs against all the bad guys. We do find some villains more difficult to beat than others, but sometimes we're doing fine against the villain and it's the environment that screws us up - we were managing okay against the Chairman once and were getting close to beating him, but ended up getting finished off by Anubis instead :(.
Heh.
Fanatic (not Promo) is my favorite hero still. And you have to understand when playing her that your life is just another resource, and use it. And push push push for Wrathful Strike to do a butlaod of damage in one hit. *laughs* She can be insanely powerful if you play her right, with a good team to back her up with some damage boosts.
Picking a favorite after her is hard to say, really. I enjoy Unity and I enjoy Tempest. tachyon is kinda fun as well. Truth be told all the heroes are fun to me, even when you never draw a gun on Expatriaret, simply because the /game/ is so much fun.
My 5 favorite heroes are:
Haka
Bunker
Tempest
Tachyon
The Wraith
(honorable mentions for Promo Legacy, Ra, and Fanatic)
The only hero that I will never play is:
Absolute Zero
5 Favorite Villains:
Dawn
Voss
The Chairman
The Ennead
Apostate (though I haven't played him yet)
Least favorite villain:
Omnitron (too swingy as he is either too easy or too difficult depending on which cards come out)
As far as my favorites behind Tempest (first Hero I ever played), I also love Tachyon, Visionary, and Legacy. I don't think there are any heroes I outright dislike (I do feel, however, that Bunker has fallen a little behind on the power curve and that a poor hand from Absolute Zero makes for an absolutely horrible game). I like playing a lot of other heroes, but these are the heroes that most consistently reward my preferred style of play and how I like to contribute to the group.
Like many others, there aren't many heroes or villains that I outright disdain. My favourites are as follows.
Tip of the Top:
Fanatic, Visionary
Fantasticly Fun:
NightMist, Unity, Tachyon, Ra
Love to Lead:
Legacy, Wraith, Argent Adept, Mr Fixer, Tempest
Could Coexist:
Haka, Expatriette, Absolute Zero, Bunker
The only heroes I would probably turn down would be Bunker, whose play style is not what I'm interested in, and I've never enjoyed heroes in mechanical suits, Absolute Zero, because...I find him frustrating and then a joyous blast with little in-between, and Argent Adept, who I thought was going to be my favourite hero ever, but required more knowledge of his deck and re-reading of all of his cards than I had anticipated, and thus, he's amazing, but not my top.
As for villains? They fit in even broader categories for me. It's pretty much this.
Villains I will play whenever they are there:
Everyone not mentioned below.
Villains I'd probably pass up if given the opportunity:
Chairman, Matriarch, Spite, Plague Rat...yep.
My top villains are probably Akaash B'huta, Dawn, Baron Blade (I want to marry him. It's tough with these guys, as they can swing so drastically depending on the evnironment and heroes. I take it as a sign of a good, fun time.
For my favorite hero, I can never decide between Tachyon or Unity. I love them both equally.
But my favorite villain would have to be Spite.
favorite villian i really love the Eniead. Oh sure, even on normal mode they kick our butts often, specialyl if a bad combination of colors comes up to trigger off all the ones up, but it still is a blast..
I hope one day to play advanced against them.
Playing alone, they're all great, I just randomize it. In groups, I usually also just play a random hero, because I like them all well enough. If I have to choose, the order is probably something like this.
1: Visionary, Argent Adept, Legacy (America's Finest) - If I can help people be awesome, I usually will.
2: Tachyon, Haka, Unity, Nightmist, Fanatic - Great power, great utility, fun games.
3: Tempest, Wraith, Expatriette, Ra - The first two are good enough that I sometimes feel like I'm cheating. The second two have less finesse than I prefer.
4: Bunker, Absolute Zero, Mr. Fixer - They take so long to set up, and have too little utility for my liking.
Villains? Again, I'll play any of them, I sometimes shy away from the last tier.
1: Spite, Citizen Dawn, Plague Rat, Ambuscade - A game against one of these villains never ceases to intrigue me.
2: The Ennead, Apostate, Baron Blade, Grand Warlord Voss, The Chairman - These games are usually tough, satisfying matches. Blade is not so tough, but will probably always tell the most satisfying story.
3: Akash'bhuta, Omnitron, The Matriarch, Gloomweaver - Akash and Omnitron just take too long. The Matriarch is tough in a way I don't embrace. Finally, it's a nice thematic fight, but I'm not convinced Gloomweaver works correctly, mechanically speaking.
Out of the ones I've played:
Great Heroes: Fanatic and Tempest. Mostly because they're the only heroes where I feel like I can do decent damage right off the bat but still contribute to the fight in ways other than just punching things for massive damage.
Okay Heroes: Mr. Fixer, Visionary and Absolute Zero. Mr. Fixer has some really great cards, but his limitation of only having one tool and one style at one time limits his capabilities severely. His grease gun is really the only reason I don't rank him alongside Bunker.
At her best, Visionary can basically cripple the villain deck. At her worst, Visionary dies three turns in or just sits around in her coccoon half the game.
I like the concept behind Absolute Zero, but I feel like the small amount of damage he deals out early in the game (as well as the fact that even doing small amounts of damage ends up hurting him) makes him inferior as a damage dealer to Fanatic or Tempest, and that his healing capabilities are not particularly useful in the long run, since he can only heal himself. Thus, his only real use is as a tank; a role which can also be fulfilled by other heroes that have better offensive or support abilities than Zero.
Worst Heroes: Bunker. When I played as Bunker, his setup took so long that, by the time I could make decent use of turret mode, the villain was already about two turns away from losing regardless. In the end, all he did was absorb damage and help deliver the coup de grace (which the other heroes could have done next turn without his assistance).
Great Villains: Apostate and Citizen Dawn. Challenging and fun, but usually not overwhelming.
Okay Villains: Grand Warlord Voss. Voss just seems like a weaker version of Dawn at times.
Worst Villains: Baron Blade, Omnitron. Blade is just easy to beat. The only time I lost to him was when I used only two heroes, neither of which was capable of reliably dealing more than three damage to a single target in one turn. As for Omnitron, maybe I've just been really lucky when playing against him, but all my battles with him have just consisted of the heroes easily destroying every card he plays for an hour before he finally died. His main challenge is his massive amount of HP, so fighting him is fairly boring.
I play a lot of random solo games, and have a hard time chosing one hero above the others. Haka is a hero I like playing, though : I like his background, and he is always useful.
I also like Absolute Zero a lot : like for Bunker, the cards you have in your hand on the first turn completely change your strategy. But I prefer his "theme" than Bunker's.
Argent Adept is powerful, but he is the hero I would rather not play - he asks for too much brain power, not a problem in solo plays, but not very fun when playing with someone.
I like the Matriarch for thematic reasons (The Birds is a movie I really like a lot), but she is always a hard fight, and often a depressing one. But random draw has me playing a lot against her avian majesty, and I begin to feel more comfortable against her. I don't like the Chairman much, his deck rarely gives you a weakness to exploit, he is worst than the Matriarch. I think I prefer Villains who don't ask you to be too "serious" and focused on finding the perfect move to survive and maybe win.
Omnitron may well be my favorite : he is not "too" hard to fight, but you have to adapt to what he does to win. Akash'Bhuta is a long fight, but always fun for me. I like Blade, but he is too often not challenging, alas. He can be a walk in the park, or an invincible juggernaut - but when he decides to play weakly, well, it is a little boring.
Gloomweaver... I don't find him fun to play against. I find myself always playing in the same way, with this one.
Edit: By the way... I just had two hard fights against Plague Rat, a complete defeat, and a hard won victory with the same team. While playing, I sudenly understood why fighting all the Rook City villain always seem "strange" to me : fighting them on their non advanced side feels just like fighting the non-Rook city ones on advanced. Plague Rat feels like he deals just a little too much damage, like if he had a permanent +1, for instance. It's like if the Rook City villains had an "advanced" and a "very advanced" gameplay instead of "normal" and "advanced".
Visionairy and Nightmist are so very similar to the characters I play in D&D where I just debuff.
Then Legacy and Expat are behind them if I want something different, then argent adept if I'm in the mood.
Favorite Villain I really like the matriarch, chairman, and Dawn. Apostate is fun too.
Spite is just rude.
I'm surprised by the lack of love for Bunker. He's not my favorite, but I still like him.
The few times I've played as Bunker, I just don't seem to be able to do anything with him except stack up the Omni-Cannon, provided he lives long enough for me to be able to use it.
Grenade Launcher, Gatling Gun and Maintenance Unit in Turret Mode is a viable card set up, too, especially if you're playing the Engine of War version.
I think that, when playing Bunker, many people become focused on something that hampers their enjoyment. For example, I hear people complain about not getting "the right mode" or "it took forever to get up Turret Mode". I've found Bunker is fun to play because I can almost always use the cards I get. If I happen to get a mode that is useful at that point, even better, but he generally always has something fun and interesting to do if I focus on what he has in hand.
That's just me, though. 
I think Rabit is right. When I first played Bunker, I used modes a lot, but now only when it fits the situation. Even with just a flak canon, Bunker is already outdamaging most of his companions. Modes are very useful, but not mandatory, he has a lot of possible "configurations".
Last time I played Bunker, by the end of the game he was in "full tank mode 2" versus the matriarch : plating, maintenance unit*2, turret mode.
Bunker is one of my absolute favorite characters. I almost always end every game with his whole set up on the table, the rest of his deck in my hand, and to make it even sweeter I usually score the finishing blow on the villain.
I do think that the key is being willing to swap modes out as needed, rather than throwing everything towards getting into a single mode. I also tend to use the extra mode cards in hand as discards that don't hurt my capabilities or things to charge my laser/keep my gattling gun around. I love having an upgrade mode in hand during my open, and if I have an ammo drop, then I am immediately set up. (and if someone else is playing Haka, who is my favorite character, then I am going to kick serious butt)
Armor plating and the maintenance unit allows Bunker to tank pretty darn well, especially with all of the lower HP heroes that have come out since the base set.
I also really like Mr Fixer, and I regularly see people hating on him on these forums too. One of the things that I love about this game is the vast diversity of heroes, so that everyone has some choice in regards to who/what they are playing. I will never play Absolute Zero because of all of the math involved, but he is my room-mates' favorite character, so to each his/her own I say.