Slash or Hendrix, that is a hard question to answer at least for me anyway. They both were great, just in different ways. Personally I like Slash over Hendrix just because I like a harder style of rock that Slash plays but in skill wise, in my opinion Hendrix is better. If said person ever exclaims Slash better than Hendrix you can give him some leeway, Slash>Hendrix in HIS type of sound Hendrix>Slash in overall Skill (song writing etc). That is all I have to say on the matter and I hope that helps you out with your little predicament with your friend over who is greater. I could actually drone on and on about this topic but it is late here (round 1:30) and I am getting to tired to come up with anymore more straight out thoughts.

-Pbyer