I installed the Nest a few days ago and found the hardware and excellent quality and installation instructions clear to follow. It feels like a top end device and the interface is intuitive and elegant. So, I was pretty happy with it until I came to use the iPhone companion app. I wish I had looked at the app store reviews before buying the unit as they accurately cover the issues I have experienced. I often fails of first launch requiring a kill and restart, accessing the schedule crashes the app half the time. The killer feature for me the home and away function does not work and the app does not use my location services. Reading the support forums there are 3rd party apps that make this work but not really something we should have to do. If I had not already spent the best part of a day installing it I would send it back and pick one of the other alternatives that try tado better. On a positive note the integration with Amazon Alexa works well though and the web interface provides an alternative to the app so all in all its workable and a big upgrade from my physical thermostat. Let hope they fix the app issues in the next few releases.