the black knight is easy, if youve got a DK in the group. just counter his army of the dead with the DK's. the lady boss, 2nd boss i think, can be pretty hard when she summons the dragon or murloc thing. its weird, we ran it 5 times in a row and she didnt summon anything until the last attempt and we all wiped because we had no clue what she was doing lol.
the gears pretty crappy in the normal 5 man if you've got any naxx gear already. that gears is basically for new level 80s to go farm and get caught up to naxx-level gear quickly. (which i like, no more spending tons of gold at 80 on items). i havent done it on heroic yet, or 25 man yet, but i can imagine the gear is pretty kick ass.