I think you will. At first I resisted since I was already ordering so much Cathe stuff. I ended up getting Vol. 4 for my daughter, who isn't too thrilled with step aerobics at this point, and I gotta say...I love it!
I believe the shorter ones can be modified into longer workouts by going back a few tracks and playing specific challenges again (Sean even mentions this option on Vol. 4). The opposite is true for the longer volumes ~ just skip ahead to the cool down when you're ready. That's what my daughter did.