I would assume that any reasonable quality thermostat that can regulate the temperature accurately would be fine with a rack. A proportional thermostat in general is good since it allows a smoother heat "balancing" act. I don't know what the manufacturers meant specifically by a "microclimate" unless it was a fancy way of saying that the thermostat is not reliable for huge distances beyond the probe. The rack that I bought has the probe in the middle of the middle shelf and seems to do the job well.