I just rebuilt my machine with a KT3 ARU, it went very smoothly, in fact the only problem that I had was the fact that I couldn't find the option to turn off the fan speed detection (i don't have a fan on the cpu header) but i found it when i updated the bios.
Despite the fact that everything went so nicely, I just sold the board. It was nice, but it wasn't anything that jumps out at you. I also wan't able to get the VCore above 1.7v. So I now have a A7V333-R on the way. I am was reluctant to change, but the few review out there about the A7V333 boast better things than the review of the KT3 ARU. I don't really want to have to set the VCore by jumpers, but there is said to be a combination allowing 2.3v.
As far as the KT3 its a great board, I would highly recommend it, it seemed to OC well, but the voltage limits that. Very stable, lots of features, and the sound is great. I really don't like onboard sound, but it sounded as good or better than my SBLive........