All other features and price being equal, go with the mobo with the latest chipset.
Did you know that ASRock is made by ASUS? ASRock has the reputation for being the "value segment" of the ASUS product line, and it is. But that is not to imply that ASRock mobos are cheap POS's like ECS and Jetway. Currently using ASRock mobos in 2 machines that have been up and running for several years without any hardware related issues. Asus certainly puts all the bells and whistles on their line up whereas ASRock equivalent may not have as many value added features. However, ASRock mobos are just as stable and reliable as Asus.