I didn’t love any of their post-Beatles solo albums (though McCartney’s s/t debut and it’s follow-up, Ram, have their charms), and I’ve always felt it was because their collective chemistry is what made The Beatles as good as they were. It was the songwriting and harmony singing (modeled on The Everly Brothers, whom they idolized). On his own, Paul is too sweet for my taste, John too sour. Plus he had Yoko dragging him down ;-).
George was always my "favorite Beatle", but he wasn’t much of a singer. He put out a pretty good final album, though. It included a recording of an obscure 1950’s Rockabilly song ("Got My Mind Set On You") that I liked a lot, produced by the great Jeff Lynne of ELO. The music George and Jeff made together in The Traveling Wilbury’s is by far my favorite that any of them made post-Beatles.