I love love love X10. I have to say that we got through Cardio Blast, Fat Burning Circuit...and halfway through Hi/Low, had to call it quits. Now maybe we should've done Hi/Low earlier, but wow!!! This workout kicked our butts and we were sweaty messes and crying for Mama ;-) I think this particular workout falls into a new category: RELENTLESS!!!! This is my favorite of all the new ones I've done. Really liked FlexTrain and Lean Legs & Abs. Wasn't knocked out by Rockout Knockout (I prefer Xtrain's Hard Strikes), but maybe I'll like it better the next time. Choreography is hard for me, so that might've been the problem. Still have a few more to try, but I'm impressed with the new set overall.