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.
 
I've read a "review" about GA-X38-DQ6, some time after Computex (was that in June?). It sounded fabulous, but you have to take it all with a grain of salt since the product doesn't exist yet. What I would recommend to you is to wait until anandtech or xbitlabs publishes an X38 board roundup and read it carefully, then buy. You might have to wait a week more for that but it's worth it.