I lived in Apt. 19 on the top floor from April through July 2010, and we had bedbugs right when I moved in. I didn't react to them, but my girlfriend did right away, and then both of my roommates found bites. One roommate and I found actual bugs, killed them and put them in a little bag as trophies.
The person who had leased the apartment (from whom I was subletting) contacted the management, and they at first refused to do anything about them. They said we must have brought them into the bui
lding, which, we discovered, was absolutely false. Not only did they appear in all bedrooms in the apartment virtually simultaneously, but the building had a history of bedbugs. (Apparently most buildings in the area do, according to the exterminator who eventually came.) Also, the tenant in the apartment directly below ours (apt. 15, perhaps?) said that he had had bedbugs too. He had spent $1000+ of his own money for an exterminator, but we luckily discovered that landlords in NYC are required to pay for exterminations.
Eventually, after several trips to the management office, they gave in and an exterminator showed up. Two of us (in the rooms off the kitchen to the west) never saw or heard from a bug again, but our roommate (in the room on the east side directly at the end of the hallway, where I think the infestation was greatest) said she still got bites and threw away a lot of her stuff and moved out.
Anyway, beware of the top floors of this building, I'd say, but for the most part the infestation wasn't so great that the extermination didn't clear up the problem.