I like the Hardcores, but the Intensity Series is my favorite series. I kept all the Intensity workouts (except for the compilation), but got rid of several HC workouts, and still have one I might get rid of because I don't use it at all.
The series don't come with a rotation guide, but after each series comes out, Cathe posts a suggested rotation (in the rotations forum: you'd have to search for the older ones). And you can always ask on the board and get ideas from other people.