I also have heard about PES being better than FIFA. But I'm FIFA fan through and through. I first played FIFA 96 must say those editions were much better than some editions released in the middle years!!! I have played 1996, 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2006, 2007, 2008 and now playing 2009!!!
The main thing about any sports game is making it look as real as possible, the players, stadiums, referees, commentary and the works. If the environment and the players don't look real and life like then half the fun is gone. Frank Lampard looks very different in PES 09. I would found it really difficult to recognize him if the name was not given to the pic. For example, would you like to score a goal with Rooney are somebody who looks like Rooney?
In that sense, FIFA 09 is awesome. EA has taken painstaking efforts to make every player look unique. Even the Division 3 players look great on the field when playing. The menu graphics have a sleek look to it. The in game videos are great.
The game play has improved in FIFA 09 although not much, passing has been made difficult and scoring long distance goals are easier now!!! They have changed the whole keyboard layout for the game... that's the one major change!! Although, you can change them back to the traditional settings.
But I have read in some reviews that this year FIFA has finally overtaken Konami or at least closed the gap. So this year I must say, this you can try FIFA 09 and you wont be disappointed!!!
The main thing is that FIFA do not spend much stress on FIFA as they do on the other franchise like NHL, NBA and especially Madden. Those games are next to being flawless!!!