There are 3 types of thermostat
Standard - like yours which just switches the heat source on and off to maintain the temperature these are normally used for heat mats and heat tape
Dimming - these lower the amount of power to the heat source as the maximum temp is reached effectively dimming the heat/light that is given off, these are normally used with heat lamps and bulbs.
Pulse - these give off short bursts of power to the heat source, the intervals gradually become longer as the optimum temperature is reached, these are normally used with ceramic heat lamps and emitters like yours.
Micro climate and habistat do all 3 kinds of thermostat, most people will reccomend habistat thermostats but i have found the microclimate range to be just as good but at a cheap price.
Hope this helps