This controller has been in pretty well continuous operation for around 3 years and worked flawlessly in that time. 

The pulse control system I have implemented is a bit lame and causes lights to flicker as the power to the heater is turned on and off.

I have started to work through a new version which will incorporate pwm control of the power to eliminate the pulses on the power line. It will also allow me to control the power with greater precision.  Stay tuned