Gspot -
Interesting comment on the EFIS/GNS being Windows based..
I managed/flew an Ultra that had a Primus 1000/GNS-XL setup...worked fine, and 'just being me' I wanted to figure out how to modify the MFD checklist...turns out Honeywell didn't support it, and of course the software was no where to be found...well I was given the link/software, that I later found out was like $5000...so I modified the checklist to recognize things like 'Enroute - Check O2/Mask' etc.
That software was Windows based, and silly as this sounds, can only be ran on my old Win 3.1 laptop, that's how old that software is.