I know they are crap but I still might buy one just to have a steam
back-up of the Dynon that is going in my plane. Odds are I'll never use
it and if I do the chance that it, or the one I replace it with failing
at the same time as the Dynon are next to nil.

Ok, maybe a good point but, even if you "don't use it" it's still
hooked up and working. So even if you "don't use it", somewhere
down the line it will either break or not but you will always look
at it and compare it the the dynon. In other words it's always on and
working, so how do you know when it breaks? If you compare it's
information
with the dynon and start to question the dynon, then you'll end up
spending
the money you saved on a mechanic looking over the dynon. Or not.
Lou