PES used to be fantastic until PES4.
PES5 not much of an improvement at all...PES6 went all arcadey and generally crap...PES2008...Again arcadey, not as bad as 6 but worse than 5...
FIFA on the other hand started crap and has gradually got better each year.
I was a PES nut from ISS -> PES4.
...Since FIFA 07 though, FIFA has definately provided the better game of football. PES is a joke these days.
The only people who think it is better are the people like me who used to love PES but never actually played the last couple of FIFA games...
Get with the times I say!
FIFA has upped its game, and is currently around where PES4 was, but with licensed teams and a much more refined gameplay, commentry is also (and always has been) FAR superior.