PLD seems best right now although GNB does deal more dmg but has problems with mitigation sometimes.
WAR and DRK aren't excatly in great states according to the community. Sure they deal enough damage to be 'balanced' but the sentiments are pretty universal they they both are fairly 'boring' especially WAR who has the worst 'downtime' of all the tanks to the point being a severe detriment to some losing focus due to boredom when IR is on cooldown.