DH > DK > Paladin > Druid, from my experience. DH's can compete with all but the very strongest aoe dps and sustain 500k+ on larger packs / double pulls.
There's a slight issue in that warriors can pull easily 5x as much and just let the dps do the work, though. If you're running havoc / outlaw / fire you're better off with a survival tank and letting them do over 2m aoe with bigger pulls. Guardian fulfils both roles, here.