what is a better brand g.skill or corsair???
Quite honestly, it really doesn't matter. G.Skill is just as good as Corsair. All name brand kits will basically be the same quality. I prefer G.Skill, myself.
As far as the heatspreaders on the Corsair's go, they're just there for looks. Nothing more. Same with all DDR3 RAM. The heatspreaders are mostly just for looks. DDR3 is very cool running RAM.