Dazed and Brutal
Yall About to Witness
I think jazz is often more difficult than prog.
Yea Jazz can be more difficult, so I did over blow prog a lil, but still. It's very hard to play in the times that many prog bands do. It's also very hard to incorporate fusion within their music while not flying off the handle.
Jazz > Classical > Blues > Prog Rock > Metal > Rock as I see it.