Ecobee, works great. Very customizable with the ability to add in sensors and run smart plugs. Logs temps and run times and creates detailed reports. Only things I dislike is the crappy touchscreen and it was pretty expensive. It was one of the biggest power saving changes I've made as I can now control the stages of my geo pump properly and keep it out of emergency heat mode. Last time I checked their site I didn't see it on there, they have a new ecobee3 model that looks more like a nest, not sure if it has all the same set up options... Other really nice part is it uses a standard thermostat wires (4 I think?) as signal wires to the main box that you mount in the utility room. The cheap unit I originally got with my geothermal required a bunch of extra wires to be run.
