Just wondering if anyone has tried THIS.. Looks like a nice, easy solution. I don't see any wattage specs on it but, according to the short paragraph, it can do the 150-190*F with an over ride to do a full boil.
IMHO, You would be far better off building a controller set up using Auber Instruments components. Your complete controller would cost about $200 including the element, switches and enclosure. Plus you have absolute temp control and boil rate control.
I have one of these and find that it's better than a propane heater. I have the 15" model and use it in my 10 gallon Blichmann boiler maker. I turn it on when sparging and the wort covers the heating element. When half way done with the sparge, about 3.25 gallons, I turn on the boil switch. It takes about 45 minutes for the 6.5 gallons to boil. Evaporation rate is about a gallon an hour. The best part is that I can brew inside and I'm not at the mercy of the weather. I use it to heat my sparge water too.