PES 2013 is much improved over 2012 but has those same trademark frustrating annoyances. The most annoying is balance/'fair' issues and this applies to FIFA too but I can speak more for PES. By fair I mean, in every match there are those situations which happen too often where no matter how much you try to win ball the back, the AI manages to get the ball back again and again until they create a chance (like it's scripted).
For example you tackle a player but the ball goes to another opponent, then you slide tackle that opponent but the ball goes to another opponent, then the opponents crosses hits my player and the ball comes back to them again. I don't know how many times I cross, hits their player and the ball goes comfortably to an opponent's feet. Or the impossible physical clearance of the ball by the AI facing their goal and magically find their team mate at the half way line without needing to move! In PES 2013 there's also the immaculate through ball through the middle that cuts your defense like a delicious cake.
No matter the tactics or formation you choose, always happens at least once in the game especially when you're leading.
And the amount of shots blocked by the AI players (not by goalkeepers). Out of of 10, a guaranteed 7 are blocked. Even if I shoot with nobody in front of me within 5 meters, sometimes hits a player( could be cause of the manual shot). And the AI goalkeepers rarely make mistakes, actually I think so far never seen an AI goalie make a mistake but then I don't have any problem with Neuer... oh wait he spills a weak shot ball and there's an attacker ready for the rebound.
There was this situation where the AI was attacking and I have most of the team in the penalty area. They hit the post twice in this attack besides a shot blocked by Neuer in between them! Call me lucky? Yes and no! In those 10 seconds or so the attack lasted, I didn't even manage to touch the ball even though I had like 9 players in the box. When the ball hits the post it goes back straight to them until they scored. When I hit the post? It goes out or straight to the AI.
There should be some more balancing where sometimes both the AI and the player have some 'lucky' moments and not mostly the AI. /End rant.