I'm a personal trainer for a Boston Sports Club, which is apart of Town Sports International, which also owns the NYSC, PSC, and WSC. All the clubs in the network are notorious for being kept up very nicely and always very clean. The atmosphere of a club in the TSI network won't be like that of a Gold's or World's. Most of those gyms tend not to attract the meat heads/bodybuilders/powerlifters, that a Gold's or World's may attract, but they are still condusive for that type of person to get a training session in.
In response to what "diamonddiceclay" said - "you'd learn more from the trainers at a gold's or world gym-nysc is for amateurs." I completely disagree. I know that in my club, all our trainers for the most part have a degree in a fitness related field and or multiple certifications. If that doesn't tell you that you'll learn more from us than I don't know what does. I'm not saying that Gold's or World's don't have good trainers, I'm just saying that I think a lot of people just assume that because Gold's and World's tend to have a lot of big guys that workout there, that the trainers at these clubs must know what the hell they're talking about. It's just not always the case.