I will say I can't really see an Evil playthrough working that well. They have got a couple of interesting ideas in there for what what be evil characters (mythic path options of Devil, Demon, and Lich plus a bunch of undead related companions you could get on the Lich route..) but actual evil choices to make it dialogue and such are all shallow, don't usually blend into the rest of the story or the characters around you. Most of the evil choices are pretty much of the "I kill you!" variety, with a handful of casual, petty cruelty for the sake of being a **** ones.
That, and no matter what you do, most of the npcs still react as if you're the saviour of the world / chosen one.
Had one major bug so far, a companions storyline requires them to disappear, but then they were still at the army camp and could be selected to join the party. Thus the next step of their quest to find them again never kicked off properly.