I have it, am reading all the use information about it, haven't used it in flight. "GO" is only for iPad; the FltPlan Mobiile(only for iPhone) with the plane facing East on the icon is discontinued. The new version FltPlan Mobile for iPhone has a plane facing UP on the icon.
What stuff I've done with it at home, it seems to "pretty good for a free App" as you wrote. Oh, and the telephone support was very good after I had emailed a question and received quick email response.
HR