Yesterday I got my copy and these are the things I found.
The AI has been improved a lot and the way it plays may change depending the team or the situation.
Yesterday I was playing a match between Honduras(CPU)VS México(Me) in the Americas Cup, and the first 35 minutes were like OMG, Honduras was so aggressive in both defense and attack, they were generating so much goal attempts and I found that the goalkeepers are so much better than PES 2011, I was surprised about(Ochoa) reactions, finally I scored a goal at the additional time, that goal lead Honduras to apply a defensive style and tried to counter attack, but despite their defensive style, I scored a 2nd goal, which completely changed their tactical plan, while trying to defend and attack, they were making silly mistakes wich lead me to score a couple of goals, after the 4th goal, I noticed that Honduras didn't try to do something, It seems that according the result of the match the AI may feel frustrated and won't do anything than waiting for the final whistle.
Edit mode is awesome, while you apply the data from PES 2011, it asks you which thing you want to import.
I edit the Mexican squad and I almost nailed to make the accurate kit, the only things I missed was a stripe in the chest and the Adidas Font.
By the way WTF with the Brazil National Squad, their kit is white and green, there's no yellow and blue shorts, all the uniforms are based of the colors white and green, but at least the player names are correct