Pros: Cheap, sturdy construction, longer cords
Cons: No automatic speed adjustments based on temperature, no 3/4 pin connectors (molex only)
An analogue knob on the back lets you adjust fan speed from 50%-99% of max.
It easily handles the load of 2x 120mm case fans at 50% speed. I use it to keep 3 cheap non-PWM 1,500RPM fans quieter, and it does a good job. Judging from other reviews, this controller works better with fans that are low RPM to begin with - apparently it will not sufficiently quiet very powerful fans. The box claims it can handle up to 5 fans, but I'm reluctant to push that limit since the box also states it is designed for up to 1.2A and AFAIK a typical 120mm fan at full speed can pull ~0.4A.
Other reviews claim when the power is on, the heatsink is electrically charged at 12v due to touching a voltage regulator. I installed it while the machine was unplugged and have not touched it since, so have encountered no issues from this.