After considering whether to buy a Scangauge 2, Scangauge E, or Ultragauge, I decided on a Scangauge E.
Installation was simple. I placed it on top of the steering wheel column. It fit snugly, so I didn't attach it with the supplied velcro. The cable went down along the left side of the steering column. I zip-tied the surplus length of cable, and tucked it in the small pocket next to the hood-release.
On the left is a moving bar graph which shows your current (short term) average fuel economy with respect to your overall average. On the right is where the gauges are displayed, e.g. instantaneous LHK and average LHK.
After starting the engine, it takes about 30 seconds for the Scangauge E to "connect" with the engine computer. After a 30 minute drive, it seems to be be working well: no problems with the auto tranny on my 1.6L petrol.
So far, so good. I'll play with the various gauges in the next few days. One thing I'm interested in is discovering the "sweet" speed in terms of fuel economy.