I have to slightly take issue with this PES6 =arcade and PES2013=simulation argument guys.
My modded PES6 PC version is by far slower than my PES2013 version on 0 gamespeed. In fact when I switched back to 2013 only a couple of days ago, I was absolutely amazed how everything felt faster. Player movements, sprinting, passing, shooting etc etc.
Now I've been playing 2013 a lot on Long ball cam so this may have had something to do with it.
Here's my two cents on the matter.
Out of the two games (at least on my PC) I would probably have to say that PES6 is the better simulation of football BECAUSE of its restrictions.
The introduction of 360 dribbling has basically opened the game up in that every individual, including so called clumsier players like Coates and Carragher for example, still feel too responsive, too light. In fact I would argue that true 360 movement should only really be felt with players like Ronaldo, Messi, Ribbery, Bale etc, (and even then I would argue that even these players, human beings, haven't really got 360 degree movement in real life) and that's because no human being whilst moving with the ball can adjust their body with such precision and versatility that 360 dribbling offers.
Playing 2013 every player feels like they can do move omni-directions, it's too responsive. Combined with the pass speed being uber fast and what you have is a game that relies on pace, pace, pace, in every department. Fast sprints (from nowhere because acceleration is all but gone), no stamina system, uber passing, uber through balls. Add to this that player support seems to have gone through the roof on 2013 in that every player to a man is just running somewhere, supporting, endlessly from end to end, combined with the CPU directness and sometimes it can look a fast mess.
Now on my PES6; pass speed is slower for a start which means it gives both the CPU AI and human AI more time to get into their defensive shape. Players aren't omni-directional so you can't really rely on sprint whoring all the time, you just haven't got the responsiveness to sprint constantly. And also, the CPU AI positionally seems better and so do your players against the counter, where there's no mass of midfield space to exploit, there seems more readier barriers to just going forward and attacking.
I was amazed when I initially switched from 2013 to 6 how I had become programmed to go forward with every touch with every player.
Now, if 2013 had combated the 'freedom' with regards to player movement and uber passing with better defensive positioning and making dribbling ten times harder with lots of control loss when top speed (or through acceleration) had been reached, the game would be more balanced.
ALSO - and this is a very important point. Even now, the CPU can only hold possession for a minimal amount of time before it hands it back over, in PES6 yesterday Man Utd kept the ball against me for, no kidding, around 1 minute of earth time....this is unheard of in current gen. They just pressed and patiently passed the ball around.
Another thing as has been touched on here, in old PES it paid for you to control the nearest player, the player had the control. In 2013 it pays for you to select your man block the CPU path, then switch to somebody else to track another run, which I've had to learn and do because of scripting and CPU cheap through balls.
PES 2011 was dissed....and in some areas quite rightly so. But the feeling of player restriction for players that weren't technical was palpable. Forlan felt like Forlan because he was faster and lighter and more responsive and Carragher, well you just couldn't run or anything with him.
My final point would be general aesthetics. You know, even now with current gen old PES just feels better and looks better, The stadiums, the pitches, the colours, the atmosphere, and I was almost drooling over the keeper animations yesterday. One save De Gea made, my God, it looked perfect.
Where 6 can fall down, because of the lack of tightness and manoeuvrability, is in the final third in and around the penalty box. Sometimes the 8 directions can suddenly feel like the games downfall.
BUT - overall, I'd have to say that a PES 6 with greater flexibility in dribbling control would be awesome.