I don't own one, but my wife & I recently joined one near our home. I go 3x day since I learned I have Diabetes.
It's a small club, and I've been concerned that they seem to be signing people up every single day. So, I've been worried there just won't be enough equipment available. At times, there isn't.
One last thing I noticed is they are very interested in you on the day you join. After the spiel trying to get you to sign up for a personal trainer situation, the staff hardly acknowledges your presence.
I've lost about 65 pounds in three months through a combination of exercise and diet. Not once has the club manager said anything positive about my progress. I guess it's no big deal, but not how I would manage a club.
With the number of people that appear to be signing-up (I've watched them sign contracts), my guess is the club is well on the road to extraordinary profitability. The question is for how long. In my day, I've seen the fitness crazes come & go several times. Just like my waistline.