Gundrak is 5, yes, sorry for the mistake. I always clear Gundrak when I have time,and I never skip Eck. He's just too easy once your DPS is quick enough to kill him pre-enrage. If you can clear the instance Gundrak is almost definitely the fastest 5 you can get, although since there's no trash in Azjol'Nerub, I might start trying to do that as well.