[quote name='PlumeNoir']which is better? GoW2 of L4D?[/QUOTE]
depends, they're 2 entirely different beasts.
deathmatch probably goes to GoW2.
coop probably goes to L4D. it's deathmatch is creative and fun, but it's not the same as gears.
that said, you should play L4D at some point, just because of the survival horror/zombie aspect.