LAFitness and Ballys are basically the same thing. They are commercial gyms so you are going to get a wide range of people that go there. At times i feel like i'm in the middle of a dating gathering because it seems like people are there just to check out the other sex and flirt and then sometimes i feel like im in the middle of a training session for the Mr. Olympia or World's Strongest Man competition.
But for me i really don't get caught up in paying too much attention to those around me. My mission when i go there is to workout and that is it. Occassionally i'll talk to one of the rats for advise or just shoot the shit with the one guy Said. But i put my iPod on and workout. If you go in with the mentality that a "gym's a gym" then almost anywhere you go, aside from Planet Fitness, is a good choice. At that point you should be looking at what they offer for the price they are asking. If they offer shit equipment and terrible ammenities but are asking for a million a year then don't sign up.
I also don't recommend using the services of any of their "personal trainers". 99% of those guys get their certification from a weekend course. It's very rare that you get someone that actually has a legit degree or real certs that works at one of the big gyms. Usually you get your legit trainers at independent gyms.