I took that in a different way; if you mean overall, and not just in that performance, then...
McCartney is in my view the greatest living pop/rock musician today. I think his bass playing is transcendent, he could sing anything, and he's one of the greatest songwriters to ever live.
Lennon is an above average guitar player, who put the song and the idea first for most of his career. But he's one of those guys, in a Jerry Garcia way, that I believe could do just about anything he wanted on guitar, it was just more a question of "what he wanted".
Harrison is, in my view, over-rated. If we've considered Ringo to be "lucky" to have been in the Beatles, I consider Harrison even luckier. He is an okay guitarist (on some of the early and mid-period stuff, you can actually hear him at the limits of struggling with some figures). Yeah, he wrote a couple good tunes, and I think he had the most lack-luster of the subsequent solo careers. McCartney was ALL about the music. Lennon was ALL about the bigger picture; the ideas, the context, the statement. I think Starr was more in line with Lennon (albeit in a very very different way) and lived up to that in his own way (thus the "All-Star Band" thing that has been so successful). I think Harrison was more in line with McCartney, but didn't live up to that in a way that I would have expected a former Beatle to have.