I go with infection. I find I am exceptionally good
with both the magnum and shotgun, and very
rarely miss the headshot with a magnum. These skills can also defiantly carry on to other game types I play: Team slayer, swat, arena, btb, invasion, so on.... I play nearly every playlist. Infection is also the playlist you can get a kill medal of over killtacular in gameplay. Which I enjoy. So my vote, infection.