It's worth seeing, if you can find it. I found it rather sad that some critics couldn't get past the Heath Ledger angle: if you didn't know the back story, it wouldn't matter to your appreciation of the film.
I especially recommend it for anyone who works in a creative field or has children, but it's not FOR children. If you fall into both of these categories, as I do, it may leave you strangely disquieted for some time, but not in a bad way.
It's a bit like Wagner's later work: about redemption through love, and through art, and whether or not that stuff actually works, or we're just fooling ourselves.
Unless it's about something else entirely, which is possible. I mean, it is Terry Gilliam.
Don't wait for the DVD if you can see it in a theater.