Well lads, it finally finished downloading... And I have to say, I don't see any difference between FIFA 07 and this (and you guys know that I love FIFA 07 and hate PES6, so this is not a biased opinion). I've had two fouls for stab tackles already, and the heading system is just as awful as it was before. Movement-wise, there's a change, but it feels strange; you can go faster, but the reaction time between your pad and the player doing what you've asked is quite lengthy.
Just played through the demo once as Arsenal, I'll give it another go, but so far I'm disappointed. I was expecting to go "well I can't go back to FIFA 07 now"; but really I can't notice that much that has improved.
Perhaps I just need to spend more time with it...
Edit: Okay, after a few more minutes with it, the movement has definitely improved. I was holding down sprint too often; if you let go, it actually shows a lot of improvement. Shooting is
great!

I just had a brilliant shot ricochet back into play from the post - brilliant stuff. My only gripe is the fucking heading. My style of play is based on passes to the wingers and then crosses in. I've had about six crosses so far end up with a pathetic header into the ground that trickles to the goalkeeper. Overall, the game is an improvement, but why have they fixed everything but the heading?!
Edit 2: Okay, after another few minutes with it, I'm really impressed. The movement is a lot better, and the shooting is just fabulous. The shot bar works perfectly, you know how to gauge your shots now and you can let rip with some screamers. The referee is also improved, but still not 100% (I've had three fouls given for perfectly legitimate stab tackles in one match already). Overall I am really pleased with it, but it's such a shame about the heading. I hope I'm just doing it wrong, otherwise they've left the heading in a terrible state, and that totally wrecks the way I play football, which is just a massive shame and a big disappointment.