Willie Nelson has played and written his own music, played and written for others, in groups like willie, waylon, kris kristopherson,johnny cash when they done the Highway Man Album. Willie has been on tour with Metallica and played guitar with them. his ability to play at a moments notice with anyone anywhere, notes and chords that others have issues with, such as G to Am on stage with Johnny Cash, He made the transition easily and backed up johnny Cash as he couldn't make the transition so easily. Willie Nelson has played with the greatest of musicians and singers, even Ray Charles ( Seven Spanish Angels) When it comes to the Guitar, there isn't a song, a band, a voice or otherwise Willie can't compliment, improve, and even Push to the limit. I would say he even rivals the playing of Eric Clapton and Jimmie Hendrix.