Eternity Vault

Raided this place through-and-through last week with my guild.
Cleared Normal Mode without noticing any major bugs, so it's safe to say most of the bugs have been fixed in 1.1.

On Hard Mode, however, there are a few nasty bugs that -- luckily -- don't seem to happen that often.

The first boss, upon enrage, kept spamming his missiles that hit everyone not ducked safely behind a pillar. You'll be better off having a DPS or two constantly on the guy to avoid hitting enrage, you'll have to heal a lot more, but atleast you don't have to wipe to enrage.

The second boss doesn't always spawn his platforms you're supposed to run to in order to avoid the lava.

The last boss, Soa, doesn't always spawn/despawn his platforms properly. Sometimes a platform that shouldn't dispawn dispawns, and sometimes there are platforms out and about that aren't supposed to be there.
Soa's Ball Lightnings also sometimes lose their nameplates, making them infuriatingly hard to spot in a hectic situation.

The worst bug of them all, however, is that people sometimes just randomly die.
We've had this happen a couple of times. We're running in after a wipe and all of a sudden half of the raid or so just dies. No explanation whatsoever. A few of us have even managed to die whilst being on the speedbike that takes you in to the last few bosses after a wipe. Dying on it is hilarious, though, since the speedbike just keeps on goin' even though you're bloody dead on it.

All in all, if you can bear the random deaths while not even in combat and a few unneccessary deaths to bosses bugging slightly, the Ops is very much doable on Normal and Hard at least.
I don't know 'bout Nightmare 'cause I haven't tried it yet.