If you're curious, I'd recommend renting it.
However, the film version is very weird, badly acted, overly symbolic, and just bad. Roger Daltry is extremely creepy in the film, and there's a lot that was changed in the movie from the album.
But Eric Clapton's scene is very well done, and I consider it the best part of the movie.
"During this performance, please feel free to let your cell phones and pagers ring willy-nilly. However, do remember that there are heavily-armed knights on stage and you might well be dragged up and impaled."
(Pre-curtain announcement at the new Broadway musical Monty Python's Spamalot)