PLD, GNB DRK WAR
War has a stronger enmity generation than gunbreaker but it suffers some drawbacks such as feeling unweildy.
Gunbreaker is fun and fast it suffers from having three physical defensive CD (Always have rampart on my bars) but only 1 Magical defensive CD Personally I'd make the longer colddown both magical and physical but drop the mitigation to 25% for the same amount of time.
PLD really is tops in everything aside from the weird combo setup now.
and DRK is always fun to play almost as much as GNB is