I am a member and I LOVE, LOVE, LOVE it.   I love that there are only women.    I needed to low intensity and as one other poster said, you only get out of it, what you get into it.   If you flail around on the boards and really put a LOT of effort into the weights, you will get a huge reward.   I love that it only takes 30 minutes and if your local curves has the smart keys you will get instant detailed feedback at the end of every workout.  It will tell you exactly how many calories you burned, how much energy for EACH muscle group individually was used and several other things.  This keeps me very motivated.   The ladies are wonderful and you will make lots of new friends.   And once or twice a week we go the reverse direction and every 2 months or so they change the order of the machines.    
All that being said, if you are young and in fairly decent shape to start with, it will only take you so far.  You are not going to get a six pack from this.  So if that is what you are looking for.  This is not the place.  If you are out of shape, do it for a year, get back in shape and then go blow the big bucks and join a gym to continue.  
It is a GREAT place to start getting into shape!