I don't know Maeda's background, but he has amazing instincts. While his strikes have power, what's even more impressive is his accuracy and even more so his timing. His flying knee KO over Soca was unreal. He was chasing Soca while throwing punches. The split second Soca changed levels to go for a takedown, Maeda (mid-stride...remember, he was chasing after Soca) leaps in the air and connects with the knee, crushing Soca's face. This is just one example.
And for being such a pinpoint accurate striker, he's a pretty wild fighter. He does some bizarre shit, such as a flying somersault kick with his opponent in the butt scoot. He's almost gone flying over the ropes from a flying knee attempt. Stuff like that. Extremely exciting.
Umeki has always fought weird. He tried that backflipping kneebar thing against Maeda a couple times in their Pancrase fight. His amateur win in Pancrase was pretty cool. He hit a weird kimura-jump-to-guard from standing. He tried it again in his pro debut, and his opponent just stood there.
Maeda is fighting Imanari in DEEP in February. A good test for both guys. Imanari heel hooked Maeda in a tag team grappling match about a year ago, so it's sort of a rematch.
Umeki is retired. :( I heard he's concentrating on graduating from college.