Ecobee 4, TP-link HS105, Broadlink IR blaster local
You know the story, first you buy an Alexa Dot. Then another Dot. And another. And another. Then you buy an HS105 to control a few lamps. And another. And another. Then you make an old Roomba work on Alexa using the $22 Broadlink. Now you're hooked.
Then the old digital thermostat on the geothermal heat pump goes wonky and you start thinking Ecobee 4 (the remote sensor is a much-needed feature in my house). BUT now I'm getting concerned about "smarthome creep" and increasing dependency on an array of 3rd party vendors.
I joined the Borg and sent Bezos another $240 for the Ecobee t-stat. We installed it ourselves in under an hour (saving $100+ installation fee) with the t-stat's onboard prompting walking Louise through the initial config.
The end plan is to control and schedule these assorted devices by different vendors with Home Assistant or somesuch. Local network only. No phoning home. ...But breaking away from the Borg will be difficult.
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IIRC, Wall Street now puts Amazon with 70%+ of jabbernet marketshare. Separately, Apple's late entry has been reported as 'Disappointing." I see less & less mention of G's model and, when I do, it is often put in as a subordinate 'specialty' device on Alexa networks.