Ok. Played the PES 2008 on the XBOX 360 for about 5 hours.
The gameplay is awesome, the graphics are naturally a lot better than the PES6 on the PS2. I hardly encounter slowdown, never on actual gameplay or corner or whatever, maybe, maybe sometimes during replays during the ending goal compilation. I'm using a 42" Plasma screen, connected through the component cable, full HD.
It rocks.
It's the first time I played the XBOX so it took me some time to get used to the controller.
The game is just a bit faster than PES2006 and it's OK.
I played both the CPU and my mate. The CPU is not half bad, the AI is a lot better in offense, not really in defense. The defenders still act like assholes from time to time, i.e. allowing cut backs. But the runs are a lot smarter and the passing is a bit improved.
The dribbling moves are improved and once you get used to the new animations it makes a lot of sense.
Shooting is quite similar, maybe a bit more sensivite.
Couldn't score from FKs, which I was able to do all the time. The ball just goes too high.
The PK look is shitty. What the fuck were they thinking?
So I'm pretty sure once the option file is out everything will be great.
Bottom line: If you have an XBOX 360, get the game. I wouldn't tell you to buy a console just for it, though. I just took over a console...
Couldn't tell you about the PS3 version and I wouldn't buy the PS2 version, it's just the same as an updated PES2006.
EDIT:
Very important! In the pre match menu, I couldn't find the sub menu where you tweak the players' attitude, i.e. defense style and where they run to. If the case is of me being blind, please enlighten me. If not, it sucks.