(I wrote this on Aug. 28th but forgot to post it. Better late than never...)
I've watched it three times in the past 24 hours since I captured it off cable video on demand. I really, really hope it's still running when I get to New York so I can see it on the big screen.
I utterly adored the show on Broadway, as you can tell from my obsessive posts about it on my blog, and I've listened to the cast recording dozens of times. So my experience of the film is undoubtedly different than the vast majority of people who will see the film in theaters or on PBS this fall. Tony Scott's review in the NYT says it vastly improved a show he only somewhat liked in the theater.
I kind of have an opposite take. Spike Lee's cinematic perspective narrows our view by looking at the performances much more closely. So you miss a good bit of stagecraft you get through a view of the entire stage and ensemble. I think that's what you said you disliked about TV or film versions of operas too. I definitely feel it here. The negative side of that is somewhat balanced by a thoughtful point of view imposed at certain points, like seeing Stew over the shoulder of Youth, observing him screw up one relationship or another. I think I'd still rather see it again on the stage. But that option isn't available, so the film is worthy record of masterful piece of musical theater.
Despite my misgivings, I found the last 20-30 minutes utterly engaging as we see Stew open up his heart to show how he failed in his adult relationship with his mother and how he regretted it. But he clearly found catharsis in writing this work, and it is demonstrated beyond all doubt in the final song during the curtain call. And the film totally captures the energy and joy I felt during that closing when I saw it. I walked out of the theater that feeling I'd been through an emotional roller coaster and could tackle anything life could throw at me. That's a heck of an accomplishment for a couple hours of rock musical.