It took us almost two hours to enter ICC because "Additional instances cannot be launched" but I'm very happy with Icecrown Citadel! In the end I think we even got Alliance first clear of the wing on 25 man.
Lord Marrowgar one shot, Lady Deathwhisper down on third try, Gunship completed on first try and Deathbringer Saurfang one shot.
Lord Marrowgar down
The Marrowgar encounter was pretty much like fighting Halazzi, Supremus, High Warlord Naj'entus and Leotheras the Blind all baked into a flying skeleton with a huge axe. It's about good movement and quick reflexes to heal the tanks and debuffed people.
Lady Deathwhisper was about decursing, finding the balance between DPS on the boss and the adds, we got her down with about 10 seconds to enrage. Healing wasn't very hard in this fight.
The Gun ship was just plain fun, I was on the boarding team jumping back and forth to heal the offensive tank and then retreating after the Battle mage was down. As Keeva showed, Rocket bear is pure win!
Deathbringer Saurfang required a lot of healing in the end of the fight, we had one person die because there were a couple of marks up ticking away for a lot of damage.
Storming the Citadel (25 player)
By the way, does anyone know how to remove the slightly annoying banner/label that's hidden top right behind my buffs? The one that tells me that I'm in a 25 man raid (as if I wouldn't know?).