Woodstock and Isle of Wright are the best of what I've seen. They playing on Woodstock is better, and there's plenty of shots of his hands, plus a good feel for the vibe of the event.
Fillmore is black and white, shot by one cheap camera -- a video equivalent of a bootleg music CD. There's a lot of interview footage that cuts into the music.
Rainbow Bridge would be last on my list. Most of it is a meandering story that leads into a brief concert at the bottom of a Hawaiian volcano.
None of these DVDs are good compared with a modern concert DVDs, so you won't be using them to show off your system.