For those of us who didn’t have a chance to go to Woodstock in person, and i was one of those, there was a saving grace, the movie itself. i saw it a couple of times with my friends, and most of us liked the way Santana looked on stage and performed. And of course it was hard not to like Jimi doing his part. And it is still hard to get Alvin Lee and Ten Years After out of my mind. But for my money, my favorite on-stage act from the movie was Richie Havens. But like i said i wasn’t there. 
I’ve seen that movie a dozen times.
I think it’s a toss up for me - Alvin Lee was pure stripped down rock ‘n’ roll. So I suppose I’d give him the edge.
But CSN was fairly mind blowing as well, especially considering that was the first concert those three performed together.
I think my vote would have to go to The Who.
Joe cocker was my fave, but by the way, was Mountain really on Woodstock 2 or is that more bait and switch that many people use Mountain for quite too frequently?