I don't know...it's the music, it's Tony, it's the boring exercises...the whole package. It wouldn't be so bad if you were brand new to exercise and exercise videos, but if you are doing Cathe workouts already, I don't see how the could have any "fun" factor whatsoever. And the moves are the same. Nothing new.
P90X has lots of new stuff. Lots of variety. That is why I say P90X anyday over Power 90.