For me i'm true lover of PES.
I used to play FIFA since 97,i have played all its versions from Fifa 97 till Fifa 2004,and in late 2003 i discoverd a new game called PES 3,at the time Pes 3 was a revolutionary.Playing PES 4 had made me regreting those years i wasted in FIFA n not noticing Pes old versions.
Now what i like in PES is this:-
1)To play PES and become a true winner in it,u have to have a good understanding of the football game itself in real,in PES unlike FIFA u have to have a vision to run the game and win as well.FIFA is just like ATARI so that's way many children like to play it.
2)Off the ball movement :The distribution of the players in the pitch is just real,i myself win the games by my skills in moving the players with out the ball.
3)Not evry player is PELE
4)Tactics: in PES unlike FIFA,a weak team can win a strong team if a great tactics is applied.
5)Invention:In PES u can invent unlimited types of tactics as well as style of play,in PES i myself have REinvented the Libero Role to stop strong attacking teams like Barca.