favorite z-wave thermostat?

[rexwilson]

I've taken the plunge into Z-wave and installed a M1XSLZW. So far, so good, and I'm controlling lighting and other devices. Next step is to add thermostats. I've searched and found some older threads on this, but the manufacturers keep coming out with new devices, and there's "z-wave plus" too. Anybody have a favorite thermostat that communicates politely with the Elk M1?