Just to put my 2 cents in, I too have a ScanGuage II, but I haven't yet used it on the HCH-II and doubt that I will until I want to read codes. The HCH-II's displays are more to my everyday liking anyways.

Where is the OBD-II port? I'm thinking it's somewhere where it might get in the way, deterring one from having it plugged in all the time.