Ok, download both and played 3 games on FIFA and 3 on PES. This year I was going to buy both games because I have friends online that play both, but after playing I could only buy one. PES. After playing FIFA it's clear that they have gone for the 'if it ain't broke don't fix it' approach, which means that if you really liked FIFA before you will like it again. But I have not noticed any differences between FIFA 10 and 11 yet which is disappointing. I thought FIFA was far from perfect so I don't understand why they have not changed anything, its the same game with updated strips!
Now for pes. It's wierd because the graphics look exactly the same, no updates here but it's the gameplay that shocked me. For the first time since playing pes since pes 2 it feels completely different. I think having not updated the graphics has allowed them to overhaul the game engine. The passing is so free and easy, the animations look real. Running with messi you cab dribble in and out at speed but not in a god like way. It's weird going back to FIFA after this, FIFA feels like a cartoon.
Bad points in the demo were that goal keepers have not really improved, referees don't play advantage and give every little foul! This can be frustrating but I am happy that konami have finally listened and have given a true next gen football game.