Ecobee is great. Everything is exposed through the HomeKit integration.

Have been using local control ecobee for 4 years, it just works and integrates perfectly with HA. It also looks nice on the wall and does its job.

I used it have a nest and with all the cloud control problems I dropped it when I bought a new house and got the ecobeee and haven't looked back.

Why so many people mention homekit? Is everyone here using apple homekit instead of home assistant? Can someone clarify?

Would you recommend buying the extra smart sensors for the Ecobee? Or is it better to manage the "average" temp across multiple rooms with just regular zigbee or zwave temperature sensors?

I suppose with the Ecobee sensors, the thermostat takes care of it for you, rather than having to write custom automations in HA yourself...

I've been using Honeywell T6 z-wave thermostat for a few years. I have occasional blips in it being unavailable recently, but that might be my z-wave antenna placement. Otherwise it's great, all local control, has quite a lot of configurations available, and can work either on AAA batteries or from the 24VAC if you have a C wire.

T5 here. It's been rock solid.

I’ve got a couple of Venstar Color Touch units. Nice thing is that they have a local API that doesn’t depend on the cloud. Bad thing is that I had to give them static IP addresses on my WiFi to keep them reliably connected. But they’ve been working really well with a static IP address on WiFi, with good Home Assistant integration.

I would start by sharing what your situation is and what your goal is.

E.g. Where do you live? What kind of heating and/or cooling and/or other climate contol system do you have? What'a the layout of the house, e.g. can you do/are you interested in zone control? Have you thought about instead of an actual thermostat using a sensor perhaps?

More importantly: What is your goal, what do you want to achieve, what do you want to automatically be handled by your home automation? Without having a good idea of that, you'll jut be slapping a thermostat on the wall somewhere that you can see in HA and ooh and ahh over the pretty picture.

E.g. My goals and requirements were: Since this is climate control, I want it to be bullet proof and just always work. So - An autonomous thing that can run even if HA or the internet is down. So it has to run locally. Programmable per day. Expandable/integrates well with other systems. Zone control (per floor/per room) since our heating system supports that. Preferably not rely on WiFi - if my router goes down, I'd like the system to keep running. Internet connection optional/nice to have. Easy and supported integration with HA so that I can automate beyond what the system can do itself.

I have been using a zen ZigBee thermostat for a couple of years and it has been fantastic.

Piggybacking off of this, are there any thermostats that will also function off batteries since I don't have a C wire? I live in an apartment and can't pull a new wire.