I love that clip; a friend showed it me some time ago.
Mark's still my favourite slap player. Maybe there are guys out there these days who are technically better but he's just got it for me, and not just because of the speed. He's just.....well.....FUNKY!! His groove is tremendous. Great tone too, I LOVE his Alembic tone, it's one of my all time favourite bass tones (unsurprisingly!!). And a lovely guy to boot; met him after a solo gig in Manchester and he couldn't have been nicer.