EV's are given at the end of each battle instead of each level up, which helps. iirc IV's have been changed in some way, overall its pretty good. Though I cant really give details.
On a side note, I beat Black. Hydregion is a whore to beat, especially when I've got a steel type, two fire types (Daru and Reshi), a grass type, and well, pretty much my whole team was weak to Hydregions attacks. The fact that my only level 50+ was my legendary doesnt help.