I primarily wanted backup for the vacuum AI and HI and the Aspen
provides both. I also wanted GPSS and that's built into the Aspen
unit as well. Using solid state gyro technology also had a lot of
appeal, rather than doing a duplicate mechanical gyro except
electrically driven.

Besides all that, you get a full HSI and RMI built in, as well as the
center section that provides TAS, OAT, and winds aloft.

Hard to beat in a 10K package.