i've watched the both of them fight on numerous occasions, obviously not in person

and i'd have to say tyson for a couple of reasons;
1; tyson fought a guy called michael spinks, who if any of you are old enough to remember was not passed his 'sell by date' or a mug by any means. he was light on his feet and could box (i.e not just a hitter/brawler) and could take a shot, many pundits said he had a similar style to ali, and tyson basically wrecked him.
Same STYLE doesn't mean same ABILITY.
Inter Milan and Bolton play incredibly defensive, everyone behind the ball frustrating football, does that mean they play at the same level? Not even remotely close.
Spinks wasn't in Ali's league, the difference between someone who tries to avoid punches but fails, and someone who tries and is damn good at dodging and weaving is night and day.
Ali was brilliant, surprisingly big(he almost seems small just because you see fights against guys like Foreman who is frankly, a damn beast, the size of the guys fist is scary), surprisingly strong for someone who can move so well, one of the best movers ever in heavyweight boxing. Its not even light feet and dancing, which he could do very well, against Foreman he stood still on the ropes and just moved his upper body, brilliantly.
Likewise, watch the vid, Foreman is sloppy and lazy but some of those punches, especially the body shots, were completely insane. Its VERY likely that Foreman had a tougher shot than Tyson, and Ali took dozens to the face, chin, body and barely looked phased.
As for Ali saying Tyson would beat him, there aren't that many arrogant ex boxers who would come out and say "he'd never beat me if I was still fighting", most are pretty humble as they get on and out of the game.
After his career/end of it he was a much much humbler guy than the arrogant man he played during the majority of his career.