it isn't too late to talk about the AC with the manager of the place you looked at. you could just call up and say you were considering taking that apartment (catch his interest) but that you noticed while you were there that the AC unit was not cooling very well and that you really need a good AC unit - would they be willing to work with you on that.

as far as the general conditions of the apartment - up to you if you want to speak up. my thought is with cheaper housing you are likely to run into sub-optimal things... but that you can pick your battles as to which sub-optimal things to accept / fix up on your own, and which to make a stand about. my thought is that if you tell them they have a cruddy apartment they will probably just figure someone else will take it... catch my drift?

one important thing however. you probably know this but i'll say it anyway - always for check for water stains/ discolored streaks down the walls or the presence of mould, both inside and outside, and any darker patches on the ceiling are telltale signs of infiltration. also look at the rooftop - see if any visible damage. if there are leaks when it rains you can get quite some damage depending what gets rained on. so if you didn't check that aspect, do. you can at very least do a drive by to check the exterior. hopefully you can remember inside if there were stains. the ceiling is very important though - i hope you did look at it.

good luck bargaining and apartment shopping.

~ waves ~