"Design" is far from my key value metric in a thermostat. When I had my Nest, it looked pretty, but I kept having to re-set the temperature because they'd add some new smart feature that didn't behave the way I wanted to. I ended up largely crippling the crud out of it to begin with.
And of course, after I sold it there was the incident where a server error caused everyone's heat to stop working, so the fact that my pets didn't freeze to death that day made a big impact on me too. ;)
Nest is actually far from great thermostate, definitely not "iPhone" of thermostate. It doesn't allow lots of manual settings and it doesn't handle anything more than simple systems well. There is lot of marketing that is blinding but not much substance. You should check out thermostats like Ecobee instead.
I wish there were an open-source Nest firmware, or at least an open-source backend. Google doesn't need to know when I'm home.