OBDII Scan Tools/Garmin Eco Route
 

I was looking through the options available for my Garmin Nuvi, and there is a device available that plugs into the OBDII port and sends a bluetooth signal to the garmin with most of the on board data. It reports to send error codes, system status, and other efficiency data as you drive. They call it "your on board mechanic".

It sells for about $100 online and it souds nice, but I'm wondering if anyone has tried it. If so, what are your thoughts?

This will have to be seen by he or she who has one, so don't get impatient while your waiting for an answer. :)