How could we know if the Bally's you're thinking about joining is crowded? And whether or not it's worth it depends on how often you go and what you get out of it.
I use to have a membership at Goodlife here I stopped going after they locked one of my friends in their building. They were suppose to be open 24hrs but the people decided to leave and didnt check if people were still there. I've never gone to a gym since.
I've had a Bally's membership for over 10 years now,and the only thing that I can tell you,after working out at about 8 different clubs in my area,they are all different.
I guess typically at any gym,Mondays and Saturdays are usually the busiest days of the week.