It's not just the speed, it's the ease with which he sweeps through the song apparently effortlessly. Not always his music strums the right chords (pun intended) in the listener's soul, but the technical prowess and the strenght of the character stand out brightly.
There's a lot more to say about Michael Angelo, but I'd rather let the music talk.
His instructional DVDs seem to work, too, since someone's been able to learn his song note by note. I bought the DVD... but I'm nowhere near that skill level, so I put it back in its box, for the time being.