I bought my ASUS from superbiiz (ewiz) and when the chipset issue came around, I called them and a very nice lady on the phone was real cool about the whole thing. Said whenever the new boards are avail just call for an RMA and we will do an exchange for you. No problem.
However after reading several nightmare posts on other forums, it would appear that reality is a different situation when the rubber hits the road. Thank God it was an ASUS mobo, and I didnt have to test them.
I intend to buy an ASRock Extreme 6, however I go into it knowing their support/backup is non existent, I'm basically on my own if something happens. All you have to do is look at their website. Of course newegg is the best, but tax and shipping would add another $30 for me on a $225 mobo, so I basically have to grit my teeth and roll the dice, hoping the mobo works out of the box.
Amazon has been absolutely fabulous the few times I had to return something over the years, and they prob will get the ASrock Ex6, but then the question becomes if they do it thru one of their sub vendors, who do i deal with if it needs replacing - them or their subvendor partner.