Ok, first the myth. George and Patti's relationship was broken, a marriage only by name.
Now the important stuff. Clapton is expository in his playing: He takes a theme and works it out, "explains" it for 10 minutes, and says something new. At least in the past.
George was the master of the 10 second lead. His playing fits into the theme of Beatles-stamped songs. Realizing that his leads had to say a lot in a short amount of time, he came up with leads and rhythms that were short but original. The opening of "I Want You" is understated and marvelous. His choice of notes and his style on "The End" are sublime and perfect.
George regurlarly said with admirations that Clapton was a much better guitarist than him. Clapton's creative, epic leads build sometimes to the point that your heart breaks. (Layla, with much credit to Duane).
I think George judged his own playing too harshly. As a teen, he sat down and learned every song on a Chet Atkins record and by all accounts played them well. His playing is inventive and instinctive, short but meaningful.
Now the funny: George was tight-fisted, and he hated the the taxman. He said of the peak of Beatledom in England that the band had so much to do with the price of the pound. So he and Clapton went on tour in Japan, and they had a fight over money. They remained friends, and they say George called Clapton his "husband-in-law". George was funnier than most folks know.