I see lots of comments that the former artist known as Prince was a “great” guitar player. That’s all relative. Compared to great “great” guitar players Prince is nominal, and he’d be the first to admit it when finding himself in the company of an actual great guitar player like Tommy Emmanuel or Fapy Lafertin.
Fapy
https://youtu.be/Wqrx48rgu6k?t=1m17s
Tommy
https://www.youtube.com/watch?v=z6UIXEDZGmg
They’re grown men as well.
I am not a guitarist, so I'm not going to try and argue who was "best." But when considering Prince's work, he is a good enough guitarist to be compared to the greats. But he goes further than that. His most recent tour was him playing the piano alone. Have Tommy Emmanuel or Fapy Lafertin gone on tour as a pianist?
Also consider his songwriting catalog. Most artists can do a few albums, but then really struggle to keep creating. Prince released a new album almost every year since 1979. That he had any of those skills would make him famous, but having all of those skills made him one of the giants of American music.