Hmm, I'll have to keep a close eye on my Nest over the next few days. I haven't had any disconnect issues with it, and just started using it this week as the weather turned colder (it's only controlling heat in our house, no central a/c).
I wouldn't be surprised though if Nest weren't exactly forthcoming with news about outages. These guys all came from Apple, and are very accustomed to the Apple way of thinking - i.e., minimal ongoing communication with your customers. That being said I have not really had any issues with the Nest and my AT Rev E router.