Asus is top of the food chain.

AOpen is not really on the same level as Asus, but I wouldn't expect any problems. Most likely place to find an AOpen board is in "white box" computers. Asus is more of an enthusiast's board, but they also do a large amount of OEM work.

I would normally choose the Asus, but at first glance the boards seem very similar (except for the black color of the AOpen). I don't think you can go wrong with either one.