I'm not buying a Nest, so please don't make that the quality target.
With the Nest, the thermostat sends data to their servers and your browser/phone app communicates to their server. What if they decide to close shop next year? Definitely no web access anymore. What else on the thermostat will stop working without a server to phone home to? Not to mention, if you want to find your foil hat, why do they need to know when I'm home or not?
Why can't we just have UPnP and connect directly to the thermostat? You might say that's too complicated for the average person, but that's the point of service people, to fix things you can't or don't want to fix yourself. Why do I have to give up so much because Uncle Joe still uses AOL?