Viconics wireless (Zigbee) work well in small commercial environments. Check out the basics of the Zigbee mesh network before you go that route, there are a few rules that must be followed or you will have serious trouble.
Honeywell has the Redlink wireless stats (FocusPro and Prestige) but require an additional device in the form of a Remote Internet Gateway (basically a router). This gets hardwired to internet access so not truly wifi.
I don't know too much about the nest but it looks like a residential, no zone solution.
EcoBee is the only truly WiFi thermostat I am familiar with and while it is pretty slick, I am not a fan of the touchscreen interface. The online management system is interesting and the WiFi is as reliable as its source.