PES 2011 certainly represents a massive shift in perspective for the series and adds far more depth to everything that the game has on offer. This is effectively the FIFA 08 for PES, the game from which things will only continue to get bigger, better and brighter. The game has evolved into something of a simulator rather than a football game. This is where the problem will lie for most people. All the small nuances, unnecessary features and impossible gameplay suddenly become perfect and logical when put in front of a hardcore fan looking for a simulator.
PES 2011 is great. It looks astounding, plays well and feels good but just know that you are most likely only going to scratch the surface of what the game is designed to do and will probably become frustrated and overwhelmed by the features and gameplay that have been designed to make it a football simulator rather than a football game. The beautiful game has never been quite so technical.