I prefer the music from the Intensity series and CTX, but I like 4DS music better than the Body Blast music or the music from the last series.
When I first heard it, I wasn't too fond of the 4DS music--like the last series, it's a bit to electronic, and sometimes 'tinny' sounding, for my tastes. But there are some tunes that have grown on me. I actually like the "scream if you wanna hear more...on the dance floor" song, and the pretty asian-sounding tune that comes after it(?) in HIS.
What I absolutely do NOT like is the repetition of music within a workout: the Kickbox/legs workout does this (as well as repeating a tune from the last series), and the second or third time around, I'm really tired of the songs.
I like Amy Bento's and Kelly Coffey-Meyer's music better.