I bought the complete set when it first came out and I love it. I also take private classes at a center that is certified by the original Pilates people in NYC. Both workouts are the same, and I can tell that Mari is a real Pilates instructor.
I got to the class once a week and then workout with Mari's classes the rest of the week (2-3 times per week). She has longer classes and shorter ones (20 min). Fits your schedule very well.
The tapes are classy, well produced, well explained. They are excellent in every way. My recommendation is get them, you won't be sorry.
Laurie