I have (2) PDA's (fault tolerance / redundancy)

An hx4700 running WinPilot I hate because I cannot see it in bright
light.

The other is an older color ipaq 3635 running GNII that is pretty
readable (acceptable but not great) in bright light.

I did some evaluation of some PDA based units by Symbol Technologies
several years ago for a customer who uses them for on street parking
enforcement (parking tickets for expired meters). They were
ruggedized and very readable. I was trying to "borrow" one to
reprogram to try in the glider but the vendor was not very cooperative.