paladins: are pretty good
bears: use to be good, theyre really just do jack shit in terms of dmg mitigation and self-healing
warriors: good if you wanna be a bladestorming tank?
death knights: if you know how to spec / play one, and not taking damage to the dace, utilizing blood shield is easier than some people make it look. And with 2 magic absorption shields, cant go wrong.
There's a whole lot of number crunching atm, but all in all if you have a DK laying around with 378 gear, Id stick with that, less bullshit, high dmg output and great survival.