If you are a hardcore startrek fan, it's a MUST buy for the Xbox360. I find the controls are not hard on the Xbox360 at all. However, some of the missions can be frustratingly hard...in which I mean, Bethesda must be a fan of the old old games that make you have to figure out some inane puzzle in order to proceed. Doable, but can get one frustrating. However it felt like a star trek mission when you were playing the missions, luckily unlike Kirk and Picard, if you get blown up whilst trying to accomplish the mission, or your friends bite the big one, you can always redo it.
It's a decent game even for the casual gamer. You won't get as big a kick out of finally being able to play the destroyer (as outlined in the Star Trek technical manual for the TOS which only has one nacelle) from the TOS era, or all the ships basically out of the star trek universe available, but it offers decent gameplay and challenging missions.
However, if you aren't a hardcore star trek fan I'd suggest investing in Marvel Ultimate Alliance first or Dead Rising, both GREAT games (though Marvel Ultimate Alliance suffers from the same problem as Legacy as far as some of the end bosses go, I about threw down my controller in frustration on one of them, if it hadn't been my cousins machine I might have smashed the 360 too, but he kept me in check...).