Actually, the only reason me (and most other King Crimson fans) tend to toss the title "The Greatest Band in the Universe" is a little story which happened when the band was just starting out in 1969. (and not because we're elitist assholes who think everything else sucks)
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1969, London. A young man came to a club to check out a new up-and-coming local band - King Crimson. The band launches into an hour of their stellar early material. The man is absolutely extatic - throughout the show, he is jumping up and down at his table and shouting
"This is the greatest band in the universe!!!!". And, when the set ends - he rushes backstage, finds the band's young guitarist Robert Fripp, and to his surprise says the following:
"Shake my left hand, man! Cause it's closer to my heart!"
***
See if you can guess who the man was

Cause if he's not an authority on great music, I don't know who is 8)
But, again, it's not that I say there's a universally greatest band that will work for everyone.
The man's name was Jimi Hendrix