I have never beaten him.... he is the most frustrating encounter, and is literally the Strawberry on top of the most aggravating instance in Cata. (obviously, in my opinion).
i take it you mean heroic dungeons..? since i havent raided anything, im gonna go with Forgemaster something something... that, or beauty if you dont have enough CC!
As a warrior tank it is near impossible to do corborus on his second phase, there is just no way for us to grab that many adds that are popping up that quick with both how our attacks works, and how we build up rage.
Erudax for me, I did him last night with 3/5 guild (me tanking, druid healing, and DK dpsing) and we went through almost 6 dps because they did not get the concept of getting in the safe zone, apparently when we said run to the stairs after the AoE we didn't make it clear enough to run to the stairs AFTER the AoE, and many time they alwas forgot which add they were killing.