I'm not cutting edge, not what you'd call an 'early adopter', so the last place I expected to find myself tonight was in 10-man Crusaders' Colliseum; I still haven't finished Ulduar. Healing as well, can you believe it?
I think it will be quite fun when I get over the shock and horror. Among the beasts encounter, only the worms are a real challenge. Positioning is very difficult, particularly as a healer with a need to stay in range of both tanks while avoiding frontal cone attacks and moving around to dispel the poison. If the worms die, you've won.
The second guy, released yesterday, is a demon that throws just about every conceivable evil shit at the lot of you: chain lightning, dots, fires, adds, even volcanoes. This is another fight where staying out of trouble and keeping in range of everyone to heal them is the biggest challenge. The add tank died on a couple of occasions because I just wasn't standing in the right place at the right time. But we got him down on our fourth attempt, which ain't bad for me :)
Interestingly, we took two tanks and four healers into the instance. I've never tackled a 10-man with more than three before, and often only two. I don't know if this is how other guilds are doing it, but it was a good move on our part. The whole raid takes significant damage throughout both encounters and with range being the issue it is I think we would have struggled a lot more just keeping everyone up.