Pettis being a primarily striker but has submission skills and can fight off his back, Glay is a wrestler who likes to take down.
Both men are extremely well conditioned, especially Guida. I think Pettis has better stand up striking technique but both men don't throw many heavy punches.
It's going to be an interesting fight. Guida is the underdog, but I think he might take it if he can push pettis against the fence and take him down for 3 rounds. His chin, cardio and athleticism might give pettis too much pressure.