I haven't owned Asus in a while. My current crop of AMD Gigabyte mobos have served me well for the most part, but they do have some issues:
1) Setting Vcore to Auto results in a significant overvolt even at stock speeds. This is something of a known GB issue. Manually setting Vcore usually sets it correctly, but I do have one board that still overvolts with it manually set to stock voltage (so I slightly undervolt).
2) No CnQ with the CPU multiplier above stock. Basically means BE CPUs are worthless since you are limited to FSB overclocks if you still want CnQ. I've heard that there are some software apps that try to manage p-states, and I've heard that other mobos don't always enable CnQ with a higher multi either, so maybe this isn't a big deal...
3) One mobo would reset voltage settings when coming out of sleep back to "auto." Upon reboot the bios would show my manually set undervolt settings correctly, but when coming out of sleep it would act as if all voltages were set to auto. Combined with issue #1, I would have a 620 x4 running at 1.3vcore at boot, and 1.5vcore after sleep
4) One board won't come out of sleep if I overclock the CPU-NB. It is a 550BE with both cores unlocked so that may be the issue, but even as a dual core the problem still exists. This could be a CPU, mobo, or PS issue so I wouldn't consider it a knock against Gigabyte.
Just my experiences. YMMV