Finally got to my copy of GSF, and played a couple of solo games: Karachar's Claw and Vigilance versus the Bareg-Threll Syndicate, and Marot's Folly, Bjarlspire, Ranak Warbeast and Uxshenti's Wrath versus the Technovores. I really enjoyed it; it's very involved, and definitely more of a brain-burner than Sentinels, but that's no bad thing. I managed to defeat both foes without too much trouble - it's possible that I was missing something major, but I doubt it. I guess I just need to try the harder Oppositions, and if that fails then there's always Elite mode :D
Also: holy cow, everything they said about Wrath was true. She is a beautiful beast...
EDIT: Naturally, as soon as I came to post on the forum I forgot all my rules questions, but they're coming back to me now. In particular, the rule that a card that comes into play at the start of a phase cannot activate on that phase. That's fine in most cases, but consider the Bareg-Threll mission Race for the Stars: It will come into play in the Travel phase, because that's when the Syndicate play missions, and during the Aftermath it will either be scrapped or flipped and recycled by a Strike Force ship. This means that its Travel event (which moves a bunch of ships to its sector) never happens. Perhaps the (T) should be replced with an (R)?