The newer Ecobee4 smart thermostat has Alexa built right in, but the previous generation Ecobee3 is still great, and Amazon will sell you one with a pair of extra remote room sensors for just $200 right now. That’s less than you’d pay for an Ecobee4, and that pair of sensors would normally set you back $79, and those are probably more useful than any of the 4's new features.