Many pros already know that a standard upgrade is to install a Honeywell IAQ thermostat! That's why you simply must take a look at this analysis on the Thermostat Wars, Honeywell versus Nest, which now threaten to pre-empt even the infamous browser wars, and cause consternation within the industry:
There are some other great thermostat brands out there (Luxpro,White Rodgers, Robertshaw, Johnson controls, etc.) so take a good look around the internet, and not just listen to wholesalers and salespeople. Lots of times the only perception customers and clients have of their climate system is the thermostat!
In general, a thermostat which allows for many settable options including the choice of swing variability is preferable, so that comfort may be balanced against efficiency. The Honeywells or Nest do not allow for this; many others do.