theres a key word there, best, meaning not the fastest. best includes writing, song flow, accuracy, tricks and wicked sounds. My opinion joe satriani is among this, hes written some really amazing songs and that are not just about speed but also have a lot of amazing little things. When he plays "satch boogie" live, the ending he throws in is insane, i'd describe it but kinda hard too.

though ofcourse we would not have our great guitarists today without jimi hendrix, he definatly was the greatest in the past and has lead to even better guitarists.

My teacher told me he read up a test was done on speed, John Petrucci of Dream theater topped it at 21 notes/second. Steve Vai at 19.