He has tapped out such names as Chael Sonnen—who he took down with a fantastic throw off the cage—Nate Quarry, Jason MacDonald and Ed Herman.
Also, he fought Anderson Silva for the UFC middleweight title at UFC 112, a fight he lost by unanimous decision.
Overall in his career, Maia is 15-4 and is a borderline Top 10 middleweight.
However, Maia has recently announced that he will drop down from the middleweight division and will now fight in the welterweight division. He will make his divisional debut at UFC 148 against "The Stun Gun" Dong Hyun Kim.
Maia dropping down to welterweight is the right decision, and it is the only one left for him, if he has any hopes of ever holding a UFC belt.
As mentioned, Maia went 11-0 to start his career, which is when it all started to go downhill for him.
He has gone 4-4 since that time and hasn't looked nearly as impressive as he did to start his career.
First, he was knocked out in 21 seconds by Nate Marquardt. He then rebounded with a unanimous decision win over Dan Miller, which was followed by the Anderson Silva atrocity.
After that he had two more decision victories over Mario Miranda and Kendall Grove. Then he faced off against the fast-rising Mark Munoz, where he lost another decision.
He followed that with a win over Jorge Santiago, and then he had arguably the worst performance of his career against Chris Weidman.
It was that fight that prompted Maia to make the move to welterweight.
With all four of his losses coming against Top 10 middleweights, there was nothing left for him in the division and no foreseeable way for him to get back to the title.
A drop to the welterweight division will likely improve the cardio of Maia, as he'll have to do more training to make sure he makes the 170-pound limit.
Additionally, with the welterweight division having a large number of wrestlers, Maia will get a chance to take fights to the ground, where he can look to submit his opponents.
The fight against Dong Hyun Kim will be huge for Maia. Kim has only been beaten by the interim champion, Carlos Condit.
If Maia can beat Kim, he'll prove that he's a threat in the welterweight division.