Gears 3 will get a high score because its co-op multiplayer feature that's been tweaked a bit
Uncharted 3 will get a high score considering its single-player is the best! Can't compete with that. So if I was to choose between the two it would more than likely go with Uncharted 3 because it delivers a better single player experience and Gears of War 3 is sort of recycled content but will be strong due to its co-op and multiplayer aspects.