I just started playing a little while ago
I'm a rank 16 (almost 17).
I've currently been playing a lot of Free-for-all and Here's my favourite class setup:
Primary - MAC 11 with Red Dot Sight
Secondary - Dual Wield Makarovs
I use Standard Grenades, Decoys (though I have found those to be hit and miss useless) and Claymores.
Perk 1 - Lightweight
Perk 2 - Sleight Of Hand Pro
Perk 3 - Ninja
The MAC 11 has the shortest reload time of all the SMGs, and combined with Sleight of Hand Pro, I can sometimes even get a reload in before the other guy has even finished his first clip. It's biggest problem is lack of ammo, but the dual wield Makarovs have turned out to be surprisingly effective.
Would you guys recommend semtex? Is the blast more or less powerful than the standard grenade? Also, would you guys recommend Concussion grenades over Stun, or vice versa?
So far I've been enjoying this loads more than MW2 in which i never bothered getting past rank 7