I just did this workout for the first time and had to write how pleased i am with it. I have done several other leaders' workouts and always had complaints. Karen's style is easy to follow, she's pleasant to work out with, the surroundings are simple and tasteful, she's got only 1 realistic person with her, not some Barbie who smiles her cheeks off. I bought it specifically because of good reviews for people with bad knees, which i agree-i had no pain afterwards or the next day. It's varied enough to keep attention, and can be adjusted to many levels. Thumbs up!