other space sims like this? Um... Well, there's Battlecruiser v1 & 2... there Battlecruiser Mill. Gold, and there's Universal Combat.
There isn't any game that does what this game does (I read the Gamespy review of BCM last week, and he even said that this game has everything!).
As for other space sims, the ones I've enjoyed are the Freespace series & Star Trek: Klingon Academy (both for under $10 now). Neigther have as many features as this one (ST:KA has many, but you can only control a starship, no small craft or FPS).
When you get the game, read the manual. Read it while using the bathroom, eating breakfast, going to bed (NOT while driving), and while playing the game. Then, read it 2-3 more times. Keep the keyboard shortcut card handy (and make a photocopy/scan it just incase you loose it).