Well, c'mon now, you can't really expect any significant comments about a product that isn't available on the retail market yet?
Chances are if you stick with the big name mobo players like Asus, aBit, MSI, Gigabyte, etc, any X38 mobo will be a good performer and it just becomes a question of features and layout from a particular mobo maker.
It is expected that Gigabyte will release the GA-5BXWV-RH in September 07. Same for the ASUS P5E3 Deluxe.
Nothing a quick and dirty google search couldn't have told you.