I just put in all new hvac, soup to nuts. I went with a wifi honeywell 7-day programmable the nest for me wouldnt make sense. Every location for the thermostat that saw any traffic would've been within a couple feet from a vent. So it's in the dining room on a far wall in a zero traffic are for a full 180 degrees. Just don't see the point of the Nest. I have a 7 day programmable for the first level of cost savings. Have remote capability to override the programming if my schedule deviatess for the next level.
$12k got me a 96% efficient gas heater and 15 SEER AC from Bryant along with a humidifier, electrostatic filter, direct vent water heater, and a new 2nd flr return to make the system more efficient and quiet down the whole system. The noise level with the 2nd return is night and day. Also has a 10yr parts and labor warranty and 3yr maintenance agreement. This is all before rebates from IRS, Peco and Bryant. And if you don't know the Bryant name, it's the same as Carrier. Will actually use my AC a little this summer. Didnt at all last year.