So... Lets make it a little competition between FIFA 10 and PES 10:
1. Crown
PES > FIFA
Why?
Its simple, crowd in FIFA is made out of paper, and they are pretty quiet, in PES, crowd is well made, and o my god - they are screaming, singing, and MOVING!!!

2. Goals
I'm not talkin about shooting, but about goals itself.
PES > FIFA
Why?
Physics is way cooler, thats all.

3. Clubs & stuff
FIFA > PES
Why?
What can I say, i think there are like 20 leagues in FIFA, and only 5 in PES + the names of the clubs are tragic, but its like this since 2006 or even earlier.
Also, there is no polish league in PES, and thats what I dont like in this game, but there is champions league though.

4. Career
FIFA > PES
Why?
Well, you neednt make your own footballer, and thats cool, but even if you are making one - you can set his abilities to maximum, and you can put yourself in first team, without doing tests etc.

5. FUN
PES > FIFA
Why?
Just listen to the polish commentators, and you will have enough of them after 2-3 matches.
Anyway - PES is a good game to play, because all passes are fucking cool!

One more thing - its a PC version ofc, so there is no doubt - PES will be always better than FIFA.