There are some nice moments in the PT scores (like, Anakin's Theme, I think it's called). I've actually only bought one of the PT scores- ROTS because it came with that DVD of OT/PT music videos hosted by Ian McDiarmid.

But overall, the prequel music is lackluster. Williams' composing definitely is not what it once was, but I also think he was a bit uninspired when it came time to write for the prequels.

I forget if it was here or on another forum, but someone had it on good authority that Williams was not looking forward to the PT project.

The most-listened to score for me is ROTJ.