Well damn. Only just now am I hearing this fully. (snippets at youtube being the only other I had heard.)
A participant had this to say at their last.fm page:
"Sunn O)))'s performance was, despite the thunderous volume, only just loud enough to drown out the sound of a thousand minds being blown. Drawing on their recent album-of-the-year contender Monoliths and Dimensions they delivered what must surely be the show of the year, mixing its ferocious guitar textures with faint traces of cello and trombone, a vocal peformance to remember from Attila Csahar, and lashings of pure theatre. Oh, and dry ice. Lots of it. Down at the front it was difficult at times to see the person standing next to you never mind anyone on stage as huge clouds of the stuff billowed Csahar's robes. He was a demonic presence, possessed of an astonishing voice: moaning, growling, splitting notes Tuvan-style, shrieking metallically, even singing sometimes, and imbuing what could have been preposterous Tap tosh with a sense of real drama. He chanted the Hungarian subtitle to "Big Church" as if in sacrificial ceremony, kneeling down at the feet of Stephen O'Malley, holding up an outstretched claw and screaming. After a riff-heavy mid-section Csahar returned to the stage dressed as OH GOD I THINK I'VE GONE COMPLETELY INSANE. In the dark and smoke we could just about make out a figure wearing a cloak of mirrors, a metallic crown, and lasers on his fingers, an outfit that Lady Gaga would have rejected as "too much". This was a ludicrous and yet utterly compelling voyage across a boundary into a new dimension of the mind, with Csahar oddly convincing as the embodiment of some sort of chemically-enhanced nightmare. At the intense finale (the near-impenetrable dry ice added to a claustrophobic sensation), the sound was abruptly cut, the lights came on, the guitarists hung their guitars from the roof and there was an audible (even through earplugs) THUMP as Csahar collapsed to the ground as if dead. All within the space of about a second. This was an act of theatrical bravado which drew gasps from the assembled, and possibly the greatest ending to any show I've seen."
...and having listened, I concur and wish I could have seen in person.
All thanks to BC for the access. I greatly appreciate it!