I would only recommend Curves if you fit this personality type:
1) You (truly) aren't self-motivated.
2) You feel a huge need to be included (doing the same things as everyone else lowers your anxiety.)
3) You will ultimately be happy with a medium increase in fitness.
4) You can't be bothered to think about workout plans, new methods, etc.
If this is you (and it might be) then Curves is a great place. It certainly is better than nothing at all. You can go with a friend, work side by side from machine to machine, talk, and be out in 30 minutes. But it is limited in its efficacy, especially over a long period of time.
Michael