How difficult Professional/top player mode is depends massively on which team you use. If you use top teams it's easy, I have no problems scoring and winning with the likes of Real Madrid, Barca, Man United, Arsenal, Chelsea, Liverpool etc. But it can get very testing if you play as a poor/average team.
I recommend anyone to never use Regular mode again, EVER. You can waltz through teams with poor players and score wonder goals at will; you pick up these bad habits/expectations and carry it through to the higher difficulties which really don't let you get away with doing that anymore. I play as Everton 99% of the time and have had to adapt new ways of playing as them, because they lack speed and skill you just can't get away with waltzing through teams anymore like you could on Regular, you are FORCED to play to your team's strengths. In that sense I appreciate the harder difficulties much more now, they make you a better player at the game and actually cause you to THINK, when Regular doesn't and gives you an easy ride. I've got it on Top Player now and enjoying it a lot more, even though it can still be tough. WE92005plusONE/woodhead4780, if you're disillusioned with the higher difficulties stick at it, you'll be rewarded for it eventually even if it can be a pain in the ass. I still think Professional mode is harder than it should be though for the supposed 'next step up' from Regular, maybe it's something Konami can reconfigure for a future official patch.