Haha...I'd be interested to see some opinions here. They might have artificial means of deflecting and dodging stuff besides being Mach ??. For example, Spider-Man dodges bullets regularly, but isn't anywhere near Mach. I realize that it's a bit different method because of the spider-sense, but there's monks who can catch arrows in real life...and they certainly aren't moving ridiculously faster than a regular person. Their senses are attuned to the task, and I'd imagine that WW, Supes, etc. have the senses and coordination needed to do what they do without exceeding Mach.
I play table tennis a lot, so I have decent coordination and reflexes and whatnot...now let's say you made my entire body bullet proof, gave me a couple of lightweight, bulletproof vibranium table tennis paddles and had a guy shoot at me. At first, a bunch would hit me, but with enough training I feel relatively confident that I'd be able to block a good number of shots...simply from watching the gun's trajectory and anticipating the shots, but not because I'm faster than the bullets. I think a similar principle is involved with them, except that if they screw up, they're Class 100+ and have amazing durability so it's not as big of a deal as if I screwed up with my paddles.