Forget "Woodstock". Forget "Gimme Shelter". "Let It Be'? Forget that too. This is, truly, THE greatest rock and roll film ever made. Why? Well, try for a moment to forget that the actual performance itself features the great artists it does (including The Band) and focus on the film itself.
This film is shot in 35mm format which gives the picture pristine look (as opposed to all other previous rock films, which were shot on 16mm). But it's not just a spralling work, this is also well executed as well. By that, I mean the production value is outstanding. The lighting is unlike any rock concert I've seen (and I've seen many). The camera work is top-notch (apparently it was done by the best in Hollywood at the time). It's also easy to see that a great deal of planning went into the production. Other concert films (Woodstock, Monterey Pop) suffer from a "last minute scramble" look that simply isn't there with "Waltz".
Add to that the shear magnitude of what The Band had undertaken. Imagine learning, arranging and performing so many songs in so many styles by so many artists in one night with only one take of each allowed. When that is taken into consideration, you have to have a degree of respect for them. Of course, I'm bias. I'm Canadian, as were 4/5ths of The Band.
My only critique would be a technical one. It seems Rick Danko redubbed all of his bass playing. Whether this is attributed to a technical problem or unhappiness with his performance is unclear. However, what is clear is that what you hear the bass doing in the audio and what you see on the screen are completely different.