I went with a cheaper zwave thermostat because the room our thermostat is in is rarely used dining room. So (1) I’d never see the pretty $300 thermostat and (2) the presence sensor would never work since we aren’t in that room very often.
I bought the CT100 which seems to be popular, but I might have selected something else now. CT100 input voltage with the Common wire has max spec of 25VAC, my HVAC goes to 27VAC. Other smart thermostats have a max input of 30VAC. The display of the CT100 is kind of confusing and large because of all the separate elements in the display. There are other similar models that have the typical display and buttons for quick temp changes at the thermostat.
Also search for “thermostat smartapp” and you’ll find several choices for adding remote sensor features to a cheaper smart thermostat. I haven’t tried these…