At the AHL level, he's dominant. He is very fluid, he anticipates plays very well, he shoots well, passes well, pinches once in a while... He really looks head and shoulders above everybody else on defense. I don't know how well it will translate though.
I don't think you could say he's "hard" to play against. IMO, he's a bit like Schlemko. People around here don't have a very high opinion of David but at the AHL level he was amazing. I think he's trying to do way too much in the NHL and hopefully Kulak won't fall into that trap. He has the mobility and the physique to be effective.