I'm surprised at the negative reviews and how many there are. An HVAC contractor put in this device when I replaced a furnace and AC equipment for a second home. I have Redlink thermostats at my primary location and I wanted the new one to use the same website and app, Total Connect Comfort. My T6 has been reliable since it was installed several years ago. No unique connection problems and no issues. I know that Resideo (Honeywell successor) has struggled a bit with the reliability of the website but I've had nary a problem with the T6 itself. When I can't reach the stats at one house, I can't reach them at the other too and the problem is obviously on the server side. Connection problems have seemed less frequent in the most recent few years. Definately not Wifi related at either location and in fact where I have the Redlinks, the internet connection is wired for the Internet Interface. . I'd buy this thermostat again without hesitation should I be in the market for a new location. Otherwise, it (and my Redlinks) have already provided several years of good service and I expect that to continue.