I just put this on 7s, but i thought i would contribute here too!

This is a good class setup to use if your wanting to get the 25 gun only MOAB killstreak

Primary: your favorite AR, 2 attachment proficiency+silencer+extended mags OR kick proficiency with silencer
Secondary: doesn't really matter, i use my favorite machine pistol
Lethal: again, doesnt really matter, i prefer claymores
equipment: i use concussions
Perk 1: Recon
Perk 2: Hardline
Perk 3: Marksman
Strike Package: specialist
Killstreak 1: Sleight of hand
Killstreak 2: Assassin
Killstreak 3: Scavenger

Explanation: This class is best for getting the MOAB mostly in part because of the specialist killstreaks. Using hardline after your first kill you get a perk (not to mention every odd number of kills you get extra XP) and after 7 kills you get EVERY perk in the game pro. When you get all perks it is quite harder to be killed with all of those abilities, not to mention its really fun too. I use SoH first because as soon as you get your first kill then you need to have a quick reload, assassin is mext because your starting to get on a higher streak and need to be harder to detect, scavenger is last because after 5 kills you need some ammo.

Here is me using this class setup with the ACR getting a MOAB:


Here is my 2nd MOAB using a similiar setup:


Here is my friend using a very similar setup that i told him about getting a MOAB: