Pettis movement has changed alot since then though, since he started moving latteraly on the balls of his feet, the way his distance game has changed and how he's evolved the way he cut's angles (probably the best fighter in the entire UFC at doing this) is reason for concern for Benson.
Pettis is alot more elusive now in his movement then he was in WEC, and Benson is a clinch type wrestler, he doesnt really shoot for TD's like Guida does. Pettis made a mistake in the Guida fight where he got comfortable fighting from his guard he knows this cost him that fight though so i'd be extremely surprised if he did anything like that again, if Pettis get taken down i think he'll work sweeps and if he can't get his hips out asap and scramble back to his feet.
He's coming out there to kill Benson for five rounds, and Benson is gonna try and point fight him, i think Pettis can KO/TKO Benson and i think he can win a decision (hometown advantage) his striking is also alot more pleasing standing for the judges eyes.
So my pick is Pettis.
Ben Askren is the wrestling coach @ rufous sports btw so i'm fairly sure Pettis wrestling will be up to par.