They are both insanely good athletes -- both are in the top 5 all-time, but Bolt's performance in Beijing was out of this world. They are close no doubt, but I give a slight nudge to Bolt.
Bolt. In a comparison like this, medals are irrelevant. There are so many events in swimming, more than any other sport. Overall I take Bolt as a better athlete.
This Also swimming has different styles of swimming; it makes it harder to dominate when someone can specialize in one field.
Both are freakishly athletic, although (IMO) swimming requires a mastery in technique as well. I am not discounting sprinting... I am sure that it requires a lot of attention to detail, but swimming is a sport in which technique can trump strength & fitness.
Everyone keeps talking about the number of events...but that can make it harder, not easier, to be great. Phelps has to maintain his concentration over a longer period of time, not just from event to event, but within an event, as well.
If they had races for different types of running I suspect Bolt could probably get a ton more medals. I'm going to give the edge to Phelps. Even factoring out more events that Phelps does he has done it longer for Bolt. If Bolt can win two more gold medals this Olympics come back next Olympics and win at least two more golds I think we can start putting Bolt into the greatest Olympian discussion.
I'm not sure how Phelps being awesome in many events is a bad thing? Would it be better if he just did the 100 and 200 meter butterfly the last 3 Olympics? Phelps has more opportunities than some others to medal but he also dominates those opportunities, nearly every time. Both guys are equally impressive.
do you ever see runners competing in multiple events to the degree that swimmers do? There's a reason for that, it's not the same/not as easy. It requires different talents. You always see many swimmers compete in many different events? Why? because it's easier to cross-train. You cannot fault Bolt NOR credit Phelps for the fact that he competes in more events, the sports are different.
I don't see much of a difference. Take a look at the US team roster... Most swimmers specialize in one stroke. And then you have Franklin, Lochte and Phelps. Phelps is a freak because he could swim all those different events and be the best at them. Even Phelps running at 85% managed to practically dominate. There simply is no measure to gauge who is better and it's rather silly too. Both are among the best.
Carl Lewis? I haven't looked it up but I believe he competed in 4-5 events every Olympics. 100m, 200m, long jump, team relay and another event I am forgetting.