Gears has the upper hand, definitely! I never died on the hardest difficulties because of some issue with the cover system, never.
Uncharted feels like Dark Sector, where you sometimes take cover on some wall/rock you don't even want to take cover on. I died many times because of a bad placement, and I was obviously pushing on the wall I wanted to "stick" on. I don't know, sometimes you roll to "stick" on some other wall/rock, but it doesn't stick where you wanted to (more like on the opposite side of the wall, I wasn't even pushing a direction or even O or X buttons). It should be automatic, but it's not. That's what bugged me in Uncharted.
So what do I usually do? Just aim normally, and press L3 when I want to have a better aim. It's better anyways! =P
Random game thought :
Why is Bionic Commando Rearmed 2 getting so much hate? We finally get a real game and they're not even satisfied... I'm starting to hate the gaming community so f****** much...