I purchased this card (to be exact, i got it as replacement after the older ASUS 5870 got vertical lines and was broken) and i am using it for nearly 7 days.
Its quite silent in in idle(at 21%), but after playing the Supreme Commander 2 it was 90C hot and the ventilator was then too noisy (at stock clocks) for me (at 40%). i tried to exchange the cooler for Arctic Cooling AC Accelero S1 rev.2, but the voltage regulators have a custom ASUS layout and aren't directly cooled now. I fear to burn this card, therefore i will try to get back the original cooler (because of VRM modules) and try to remove the plastic cover and use my own 12cm silent fan to cool the heatpipes.
the GPU voltage is unlocked and can be adjusted by ASUS Smart Doctor.
VRM temperatures are unfortunately not reported (at least the GPU-Z 0.4.2 wasn't able to read them), only GPU temp1,2,3.
I am sad about the really noisy VGA coolers, they are selling these days.
and 3rd party coolers usually cool only GPUs and VRMs are left for dead ...