Buying a ScanGaugeII tool

I just purchased a Scan Gauge II from thinkgeek.com, and found it to be very interesting. I would like to know if anyone else has one installed and uses it regularly.

I have one. I like being able to display my real speed and water temperature. I also like the ability to read CELs, which is why I bought it. MPG figures are OK, but not all that accurate.