I did a mini-rotation of these for three or four weeks when I first got them,but doing them every day, as they suggest, is definitely overtraining, at least it was for me (and it gets boring rather quickly, as the workouts are all very similar). I also felt that, while my lower body was getting blasted, my upper body needed more heavy-weight work, so I would throw in a Cathe upper body workout.
I would suggest using the SS workouts every other day (with an occasional back-to-back use of Firm it up with one of the others), and using other cardio in between.