Ahh the pains of Naxx on a 22% Horder pop server, the recuitment pool was small, but at the same time it meant we was the only real raiding guild on the horde side so any decent player come right to us. We still got all server firsts in there and whole of vanilia but the 4H was a cunt, only reason we got it down was because we had some very well geared alt tanks (we let everyone bring alts to raids when on farm), and we pocached both tanks from the guild below us we had to gear them up a bit to get the 4 piece bonus (our alt tank were better geared when they joined). I seem to remember a grahpic bug as well that meant on certain graphics cards the void zones would not display.
Have to say thought you take away the 8 tank requirements and the void zone bug the fight was not that difficult and in someways was quite forgiving for mistakes