Almost every thermostat on the market has a physical fan switch, which means that it isn't very flexible (either "always on" or "auto"). What I've been looking for, and what the VisionPro 8000 has, is a programmable fan. The VisionPro actually goes one step further and has a "circulate" mode where it randomly runs the fan 35% of the time. So now the fan is programmed for "always on" from 6-8am, "circulate" from 8am-6pm, "always on" again from 6pm-11pm, and then "auto" from 11pm-6am (which means it will only run if the heater turns on).
It was really hard to find this thermostat. Home Depot and other retail stores don't even carry it yet (only available to "installers"... or people with Internet connections). Once I knew what I wanted, ebay was far and away the best price around.
So far so good... our downstairs is warmer!