I'm not a fan of most of them. I can do so-so on Turbine with a sniper and York's akimbo pistol set up.
My favorite maps are Standoff, Express, Slum, and Hijacked. I run and gun on these and when I've had a decent connection, I can rack up a lot of kills quickly. Aftermath is a campers paradise as is the Yemen map, and I've had little luck with Plaza for some reason.
The biggest problem with this game for me is the connection issue. I was doing great last night and actually had a couple of matches where I went above 20 kills with fewer than 5 deaths. I even had a couple 10 kill streaks. As is all too common, we would always merge with another lobby or get a new host and my connection would just fuck right off.
I'd see someone running toward and corner and would get in position to ambush them. I knew they didn't see me - they were facing the wrong way - I was behind cover, gun up, and finger on the trigger. I got shot in the head and as I was falling back dead, the guy comes around the corner firing. In the kill camera, I'm just standing there looking out the door.
In express, I came up the elevated walkway and saw a bunch of enemies. Having only pistols equipped, I bailed and ran back down the stairs. I got all the way to the middle landing, took hits, and was killed. On the kill camera, I was still out in the doorway of the elevated landing.
The game can be a lot of fun, but the connection issues are awful. Its probably the last game from them that I'll ever buy.