First off the negatives, and while Konami should be praised for upping PES' presentation to the next level, the occasional lack of polish can bring it down.
Faces might be more detailed and reflective of their real-life counterparts, but the occasional crack does emerge the more you play. Teeth in particular appear to be an issue Konami's developers have struggled to grapple with, while the players' arms can look static and poorly defined.
It's only during celebrations and close-up interactions with the referee that these problems crop up, so it's just a relatively minor problem. Still, when the rest of the presentation is as good as it is - even better than FIFA's, in a great many respects - it's easier to notice when things aren't running smoothly.