This thread also might give some insights...
http://forumserver.twoplustwo.com/27...d-room-373668/
My personal opinion a year ago would have been...
Taj
Showboat
Borgata
Bally's
Caesar's
Harrah's
Tropicana
A couple of things before I move on to my current ratings: even the bottom of the barrel in AC is OK to play in if you're just looking for 2/4 LHE or 1/2 NLHE. They all have decent comp systems (although I don't know what Trop's comp system is) and you'll have good and bad dealers wherever you go.
My ratings currently would be:
Borgata & Taj (tied)
Harrah's
Caesar's
Tropicana
Showboat
Bally's
The Borgata has gotten a lot better for low-limit players since Stan has made his presence known on 2+2 and the 1/2 PLO game runs regularly on the weekends. Additionally, they have the best game selection in AC in terms of # of tables available for each game they spread.
The Taj still has lots of action players and a great variety of games, plus their comps are the best I've seen in AC.
Harrah's has a nice room and I've had a lot of fun playing there. They sometimes get bigger games and they have the best game selection (# of tables) of the Harrah's properties in my experience (although maybe Caesar's is comparable).
I've always had success at Caesar's. Three negatives: don't bother asking them to spread anything other than 1/2 NLHE and 2/4 LHE; a couple of their dealers are bad to the point that I've spoken with floor managers about them; and it's like pulling teeth to get a rake reduction when the table is shorthanded. The last time I was there, we were playing four-handed while the three other players at the table were on a walk. I asked for a rake reduction and the floor said, "No, there's seven players here." I said, "OK, I'll wait." And we sat there for almost two minutes before the floor came back and approved the reduced rake.
The Tropicana has good game variety at the low limits. Lots of times you'll find stud, O8, 3/6-5/10 LHE, etc. The dealers are sometimes terrible but the floorpeople and waitresses are friendly and competent. Also, if you want to do anything other than poker, the Tropicana has tons of fun stuff to do.
The Showboat was once my favorite room in AC. The energy and enthusiasm of the staff in the room when it first moved to its current boardwalk location was infectious. The room was bustling. The floor was willing to spread any game that had enough people to run. But somewhere along the way, I think upper management stopped listening to poker management and the room fell off. That story is chronicled well in the Showboat Atlantic City thread here in B&M. The Showboat still has decent dealers and decent 1/2 and 2/4 games if that's your thing, but don't expect anything else to run in that room.
Bally's has a 1/3 game that is decent, 2/4 LHE, and 1-5 stud. They do a good job of tracking your comps and everyone is usually friendly. The times I've played there, the room was pretty dead so that's the real reason it has the bottom spot on my list.