so, I went to Sethekk Halls for the first time today. 5 man party, all of us had never been there before.
Used tactics show here: http://wow.tentonhammer.com/index.php?module=ContentExpress&func=display&ceid=656
First boss killed in 1 go. Second boss took us another try. We didn't really know what to expect the first time. Wonderful run, wonderful people who all knew how to play the game and use their character in our advantage.