I've played my fair share of these from Dark Messiah of Might and Magic to the recent Star Trek game. I'll explain the ST game since it's my most recent purchase.
Star Trek (360): This is the shooter that's based on the J.J Abrams movie and its between Star Trek and ST In to Darkness, the graphics are okay they could have smooth the characters out a bit, the voices are done by the actual ST actors so that's a bonus, You get to see a bit more of the Enterprise and you get to use it in one mission, it is a typical Gears of War Clone but it's only you and Spoke and not a whole squad. The game's story is typical for a ST game but I do have a minor issue with it.
The collision detection seems off when you bump into other people (sometime you'll merge into one) and the controls are borderline bad but still playable once you get used to it. Star Trek is a great game for a rental and maybe buy if you're a fan of the Abrams ST but I wouldn't pay full price for it unless it's a bargain bin or below $20.00.
So any of you guys played any Iffy games?