Curves is a gym made especially for women. You don't have to worry about what you look like or who you have to impress to go to this gym. It's a good workout for women however it's not real diverse. They don't have that many machines to choose from so after about a year you don't have too much variance to choose from.
It's a great place to work out but I wouldn't buy a long membership to this place. Try it out. You might find that you like it and lose weight at the same time.