BM hunter: Super tanky pet or pets with amazing threat generation. You can do excellent damage and survivability with FD.
Paladin: Very good survivability. Plate armor. Blessing of Kings. Self heal. Lots of cooldowns for defense and offense. Best soloing non-pet class. As easy to play as a DH.
DH: There is before you get Demonic and after you get Demonic. Once you hit lvl 110 and get Demonic, you solo like a paladin. You are very tough and do a ton of damage and your leech improves in demonic. Getting to 110 not as easy as a paladin or hunter.
Warlock: Demo warlock easy to solo much like BM hunter. Strong pet with good threat generation. Lots of tools for defense like fear and drain life. Not sure on the other specs, but Demo warlock nearly as good as BM hunter and better in some situations when you can use fear.