I flew the Gizmo 1000 when I was with CAP. If a sensor failed, a red X would appear indicating that feature inop. The MEL wouldn't allow much, so the airplane was grounded. Too fragile and complicated for an airplane required for daily, reliable ops, at least when I flew it.
We have a Honeywell glass conversion in one of the airplanes I fly and always seem to have one problem or another. The steam gauge airplane just presses on and on. Guess I'm biased, but I'll take steam gauges, a Universal FMS and an iPad for what we do with the one airplane over the pretty, Honeywell glass airplane.