Like most of you here, I preordered a 8GB Nexus 7 from the Google Play Store soon after the announcement. However, when J&R had their 4th of July sale, I bought the 16GB for the same price (free shipping + no tax) and canceled my Google Play order.
Yesterday, I got a shipping notification from the Google Play Store so I called today to see if I could refuse shipping, and the customer service representative told me interesting news regarding the warranty:
He said if I ordered from a retailer other than Google, all warranty claims would be handled directly by ASUS. That could mean shipping to/from and a wait for your device to get repaired.
However, if you order from Google, all warranty claims will be handled by Google, and they will ship an advanced-replacement no questions asked with free shipping of your old tablet.
Thought I'd share with the community this information. This news is enough for me to just accept my Google Play order and cancel my J&R order considering this is a first-generation device which could have some manufacturing bugs in it.
You can find more information here