What do you want it to do? Do you want remote access? Programable? Energy efficiency important? Does it need to connect to other HA type systems?

Nest is good. Ecobee and Honeywell also. Stay away from Control4.

Remote access and easily programmable would be best.

One issue with Nest is that it is preset (I believe) to using an adaptive, learning recovery for setbacks that people either love or hate. Due to popular request, it's now possible to turn that off to use a more conventional time-based scheduling. To each their own preference, that's a better approach.

You'll pay a premium for Nest. There are many other thermostats, like Honeywell's, that offer the same features (including remote access) for less money. Be sure your HVAC system is Nest compatible, I believe not all are.

My Nest was set NOT to be adaptive, it had to be enabled. Either way, when I installed it over three years ago, all the various options were either set off or prompted you to make a decision when you first started up.

A lot of the pros here dislike the Nest, and I understand the concerns they have. However, it has worked well for me. Honeywell is often recommended by the pros, and Ecobee is popular for those wishing multiple location temperature inputs.

I installed a gen 2 nest in the duplex I rented. I lived close to work and would come home on my lunch break. I also liked it cool (68) in the summer. It was nice to walk into a cool house and leave knowing it would adjust back to about 74 while I was gone. I was very happy with the nest and would purchase again. I also liked turning on the heater from my bed via the app on cold mornings. It paid for itself in the first year. I would buy again.... but I’d make sure it could hook up to Alexa or Siri.