In his prime, he was quite simply astonishing. I mean, I grew up listening to the Jackson Five, and even so, after watching the Motown Special where a lot of people got their first good look at the Thriller-era Michael, a bunch of us--including people, like myself, who never bought a Michael Jackson record in their lives--looked at each other and said, "Wow."
As for the rest of it... a good object lesson in the dangers of getting everything that you ever wished for.