I havent tried Arcatraz on Heroic yet, but thats one of my goals, I'm afte the title of 'Champion of the Naruu' before the expansion comes out
Black Morass is great with a decent party, the drops are really nice for such a short instance and it's a unique format.
If you're running Dire Maul, remember to bring the Crescent Key and or a rogue
Good fun, if somewhat long, but it's fun to wander around the former 'High born' lbrary.
Also, did you notice the Scarlet Monestary bosses as children whilst exploring old Hillsbrad?