According to some other thermometers, it seems to be keeping the liquid a bit colder than the setting. It's anywhere from 2-8 degrees colder, depending on which one I use.

I think I'll probably switch back to my tried-n-true Johnson Controls thermostat for the batch I brew this weekend.

I haven't tried the heating mode, yet. One thing at a time.

I have not tried it with a beer, yet. I've put the probe inside the container under the lid (not in the water), above it, below it and beside it. I haven't taped it to the outside of it. I'll try that while the next batch is fermenting, but I won't be using it to control the refrigerator - just so I can watch it.