Product review (4 stars): Definitely Does The Job
I purchased this controller to work with a chest freezer for a fermentation chamber.  I will start by saying that this unit does control the temp of my wort within a pretty tight (3 degree F) range.

My only problem is that the temperature on the dial does not seem to be very accurate.  I have placed my probe into the mason jar of vodka that I have for the terminal end of my blowoff tube, and to test it, I also placed a separate thermometer that I know to be accurate.  The temperature frequently gets about 5 degrees higher than the set point on the controller before the freezer kicks in.  Thankfully the fact that my 5 gallons of wort responds slowly to temperature changes (yes, I monitor the temp of the wort separately... I know... Geek) means that I can make the adjustments and pretty much let the controller do it's thing. I just do not know if I would be comfortable using the controller without knowing the ambient temp in the freezer or the core temp of the wort.

That said, this controller does the job for me and was able to do it for a very reasonable price.