I vote for Gears (in general let alone 2).
Been playing Uncharted 2 (somewhat slowly, only play it every other Thursday at my cousin's) and I'm very unimpressed by it. The voice-acting is great, as are the graphics, but the story really doesn't pull me in. It's like an over budget, over-the-top Hollywood action movie.
Actually the whole game lacks a sense of 'realism' for me. When I play a game, I suspend my disbelief so I can get caught up in the games mechanics, storyline, character, etc. Uncharted 2 fails in this regard for me. The game intends to be set in modern day, following the adventures of a 'normal' person, and it fails at this.
I find myself thinking often "this isn't even possible", so often that it severely detracts from the experience. The graphics are cool, and while the story has seemed a little soft so far, it's picking up (on chapter 21). But some of the action sequences, whether cut-scene or not, are wayyy over-the-top. If in U3, we discover Drake is actually a genetically modified human, my first thought would be 'OH! Everything makes sense now!', and that's unfortunate, because it doesn't seem like that's what the devs are going for.
It's like watching some of those old action movies where the hero takes 10 bullets, and still runs/walks around like its not that bad. It can be entertaining sometimes, but there is a point where it's too much.
Gears on the other hand has a GREAT sense of realism, and a great atmosphere. The whole darker tone is really well done, and I know someone commented on the gray of Gears versus the colors in Uncharted, but I personally like the gray. It's darker, dirtier, and really adds to the intended mood.
It just feels like Gears is like "Yeah, I'm badass, so what?", whereas Uncharted is like "Oh oh, check this out! This scene is cool. Then run over there, this scene is better!".
The gun-play in Uncharted 2 is just pathetic. I was expecting something a little more exciting than Uncharted 1, but they didn't really change it much/at all.
All this and some games have FAR too much going on in terms of cinematics lately. I want to play a game, not watch a movie that's partly (sometimes barely) a game.