McCartney is a better guitarist than Harrison or Lennon. That's him soloing on Taxman, also compare the solos on "The End", Paul's smokes George's.
Back in the early days Paul was going to be the lead guitarist but he froze on stage.
Paul was definitely the best musician in the group. I don't think that there is any musical instrument he hasn't mastered.
I remember years ago reading an interview with George Harrison, and as they listed to various Beatles songs, the interviewer would say "Love your guitar on that song George!" George would reply: "That was Paul."
Reminds me of the hilarious interview where John and Paul were asked if Ringo was the best drummer in the world, and John replied that he wasn't the best drummer in the Beatles.