Viper's Lair has posted a review on the Thermaltake Smart Fan 2
One good thing about the Smart Fan 2's thermal probe is that you can place it close to the center of your case, where it is warmest. In this scenario, the fan is likely to spin faster, since it's warmer, making it a more useful intake or exhaust fan then before. Unfortunently, the problem I see with the Smart Fan 2 is that the sensor has to detect 55°C in order to spin full throttle. If your case temperatures reach that speed, you've got some problems.Read more