I'm finding as others are - Superstar is more open and frankly easier to score than Prof. For me, Prof has been cpu playing deep sitting stodgy defence, with no space to get a decent cross or shot in.
However, for me, the referees have been much more balanced on prof. I can challenge a player and win the ball. On Superstar, the referee only referee one way - every challenge I make is blown for foul, and usually yellow card.
Yet every sliding tackle cpu makes, sliding right through my man, bringing him down in a heap, is never blown. Replays show that they actually made an implausibly perfect tackle, every time. To me, that's still a cheat - cpu becomes too perfect.
Like someone else said, these match stats always end with about 10 fouls by me, none by cpu. That's not balanced.