I've been a 24 Fitness member for about 7 years and have had the opportunity to visit a number of their clubs throughout the country. Unfortunately, my home club in Phoenix is not the best.
Don't get me wrong, it's relatively well-maintained (despite being in a run-down strip mall) and they always seem to keep things clean and in operation. They have a nice mix of free weights, machines, and cardio equipment. I tend to go in the evenings and there is never a wait for equipment. The locker room is ok, though I rarely shower there (would rather just go home). I've also never taken advantage of their classes.
My only real complaint is their hours. They close at 9pm on weekends. Since I travel most of the week, I typically only go there on weekends and its tough when they close so early. It's pretty annoying for a place that's called 24 hour fitness. Sure a name doesn't necessarily mean much - TCBY is NOT the country's best yogurt, Best Buy doesn't always have the best deals, and 31 Flavors never has 31 flavors (they usually have more - I've counted), but I certainly don't expect a place called 24 hour fitness to close as early as they do....