I rate the PC demo a B- / C+.
The graphics are definitely better. Very polished.
The gameplay seems good, although the running is just odd. Looks like they are moving their legs way too fast. Running on a tredmill

. ( I really hope this is not the case on the PS3 version). The one thing I love about the PES series is the realistic feel of the gameplay and tredmill running is a negative.
Another thing i find odd is the shooting. I haven't gotten use to it. Feels weaker than PES6.
Finally, I don't know why but the ball physics (gravity) feels a bit off too. Balls seems to drop too fast.
Altogether I feel that the PC demo is alright at best. I don't like how the gameplay seems to have suffered. This is my view though. I'll have to see how the PS3 demo reacts. Maybe its just the PC version.