Hi Eva,
I just bought Super Callanetics (used VHS, through Amazon) and I've used it 6 times within a week and a half. I love it! It is super tough. My abs have never been so flat! And I'm getting those 2 lines down the sides of my stomach. My thighs are slimming, also. The only cardio I've done is walking daily. This new routine of mine was a change from my high intensity, running 5x a week routine. I've noticed my appetite is smaller, also. According to the reviews I've read, Super Callanetics is different from the original in that it spends less time setting you up. Rather, there is a 20 minute section in the beginning where she demonstrates each exercise and shows you proper form. Then during the workout, you move quickly through the exercises. I prefer it this way, since once you know the set up, you don't have to waste time hearing her talk. Plus, I add this on after walking, so I'm already warmed up, and I skip the warm-up stretches in the beginning. (There are additional stretches throughout.) So the actual workout is probably 45-50 minutes without the warm-up stretches, and about an hour with. According to reviews, Super encompasses all, and more, of the exercises from the original. I'd say if you are already relatively fit, you can just buy Super and work up to all the reps.
Hope that helps,
Elaine
PS Read more reviews through videofitness.com (search their forum) or Amazon, which have a ton of reviews.