Demon hunter - started off pretty weak but by the end of act 2 started to pick up. I liked the elusiveness of the character but nothing really shined. It really was better against trash mobs but not so good against the bosses.
rating - 7.5/10
Witch doctor - at first glance this character has some cosmetic oddities so most people will avoid playing it. It actually felt the most powerful, switching between summons, damage, and utility was really good. Although it felt too easy at times.
rating - 9.5/10
barbarian - whomper stomper. Never had a problem, by far the easiest class being so tanky and having such good damage. It started getting somewhat hard later in nightmare, but still the easiest.
rating 9/10 - a little too easy.
So hopefully blizzard buffs the demon hunter a little bit and nerfs barbarians early game. thanks for reading.