I started using it this year (1 race weekend so far), and like it a lot. It also integrates seamlessly with the RaceRender 2 video processing software, which can add some nifty data overlays to your incar video. Here's a sample from May - the RPM and throttle position came from my Megasquirt logs, the other goodies came from Trackmaster. You can see the lap timer display it provides on my dash - the layout is very configurable so lots of other options are available.

http://youtu.be/UaOv7-kw3rs