I totally separate the artists from their work. I like Oasis and Blur's music a lot even though I wouldn't touch Liam Gallagher and Damon Albarn with a ten-foot pole, and there are endless similar examples not only in music, but literature, etc.
If Bono had a giant ego (which he has) and a tendency to be pretentious sometimes (which he has also) -AND- treated other people like shit then I guess I wouldn't like him much either. But everything I've read about him and the rest of the band has led me to believe that they're all nice, decent people who just happen to be incredibly ambitious and driven and yeah, sometimes pretentious (but isn't ALL art pretentious anyway?). And Bono seems to spend a lot of his energy on actually praising the other artists & bands to the heavens rather than bashing them.