So far so good. For something that's still in closed Beta (but without an NDA (*phew*)) I have to say it is amazingly stable and a damn good product. I'm keen to see it with some of the wizz-bang graphics options turned on, but I imagine that the client would have been HUGE with higher rez textures.
There are add-ons already hitting the interwebz on Curse. It would be good if the WoWAce community jumped on the band wagon and started putting up a development framework "to rule them all".
There is already work being done by Kaelten and Aiiane to port as much of Ace3 to Warhammer Online as possible, and this makes me a happy little person.