I'll be honest, since the end of PRIDE I've lately not been watching much MMA outside of UFC (occasionally K1), and I've never heard of this guy before. He's got an insane physice and some great power in his hands. 95% KO rate and hell, knocking out Mark Hunt alone is impressive!
How would he fare in the UFC, or more MMA fights in general? With a solid ground game he looks like he could be a decent contender, even though he's lost a decent number of fights to mid /low tier UFC guys.
After watching a few of his fights, specifically the Strikeforce debut with Robbie Lawler, he may have somewhat of a glass jaw, which sadly no amount of training could really 'fix'. I certainly don't see him being a champion, or even top 5 really, but man he looks to be a fine addition to MMA. I'd love to watch him fight for entertainment value alone.
Again I'm sure this guy is old news to people who follow other organizations, but he's new to me! Here's a 2 minute highlight video I found of his.