Summary: Don't touch it with anything metallic after power has been applied to it.
Pros: I've had it in my machine for a month atleast and it's been doing its job perfectly.
Cons: As others have stated it will ground out if anything touches its heatsink and I believe them. So be weary of that, once its bolted in it should be fine just make sure nothing metallic will swing around and touch it.
Pros: Works well when it worked. The pigtail controlled all three of my case fans together. My HTPC was dead silent at the low setting. Pretty easy to install and use.
Cons: Died after about 18 months. One day, the computer turned on, and all three fans were at maximum speed. Turning the knob didn't do anything. I don't know what happened and I can't open the assembly to see if anything was burnt out. The little assembly isn't designed to be opened. Maybe it overheat...