R870MCS - Easiest shotgun. works well ADS as well as f-rom the hip. Limited Range
S12 - One of my favorites. It reminds me of the USAS from MW3 except it's not auto (I didn't use the USAS auto EVER). Keep it close.
KSG - The quick scoper of shottys. Once you get the hang of it, it'll give you streaks. I don't think it's consistent enough to be among the best.
M1216 - This could be the best CQB weapon in the game! Once you get the hang of the 4 round burst, you can put up quad feeds. My secret is a close by TI for immediate Revenge medals, and time to reload...