There are 32 votes for Uncharted 3 in the poll; I wouldn't have guessed there were that many people here who OWNED a 360 (as you were to have both to post, right)? HAHA, just kidding.
The Gears universe and it's inhabitants resonated with me in a larger than life way (probably because they are in a larger than life struggle). Additionally I have personally found no other multiplayer game that has the same visceral appeal of Gears.
The two together make Gears the choice for me, though I will be lucky enough to play both.
SEE, you CAN state a preference for a game without insulting the other - it IS possible!