I personally loved the voice acting in XII and must say it's easily their best effort so far. Of course this is coming from somebody who suffered through the horrible English voice acting of Xenogears (Bart sounds like a girly man trying to play act a biker... while Emereldas sounds like the retarded Rei Clone that escaped from the cloning tank.) It left scars I tell you!

I even liked FFX voice acting for the most part except for Yuna's voice who makes the mistake of playing too close to her Japanese counterpart without relaizing the subtle nuances that allow the Japanese version to work.

As Bolivar said, it's the little details that make XII's voice acting excel. The use of different dialects for different regions and so forth really added alot of depth to the game. I heard the Japanese version is similair to this which is another thing that amazes me to see that the localization team put the extra effort into making the game just as good as the original. Only the MGS team puts in that kind of effort.