My mom and I went to Curves for a couple of months.. personally, we didn't really care for it. We wound up opting for a more traditional gym.
I think it depends on your current physical activity. We were pretty physically fit (not much weight to loose- probably 5lbs for me and maybe 10 for my mom?) and although we worked hard while we were at Curves and eat decently (better than normal), my mom lost like 2 pounds and I lost none. I went to the YMCA and lost those 5 pounds easily in a week or 2.
I think Curves is great for people who are just starting out or elderly women who just want to get moving.
Regardless, give it a try, just to see!
EDIT: Just wanted to add there were no computer programs when we went.