I think he's 4-4 outside lightweight, losing as much as he's winning. Wins coming against mostly MMA non-contenders; losses coming against top competition. I guess it all depends on a person's interpretation of success.
Here are his victories.
1. Bang Ludwig
2. Takanori Gomi (you know, the guy who ruled Pride Bushido)
3. Rodrigo Gracie
4. Renzo Gracie
5. Matt Hughes (he won the belt, and numerically should be first, but I leave him here because this was when Hughes was unbeatable at WW)
Not a bad list.
Here are his losses.
1. GSP (Split decision)
2. Hughes (He was winning prior to the third)
3. Machida (who outweighed him by 35 lbs)
4. GSP (He was overwhelmed by the superior athlete)