I have a 530 and a 430 which I use all the time. There's a bit of a learning curve but no big deal. I also have a Lowrance hand-held GPS (forget the model number, but it cost about $600 iirc) strictly as a backup in case I ever find myself in IMC with dead electrics. Not very likely considering the amount of actual time I get to fly round here, but would be kind of annoying if it did happen without a backup. For the same reason I carry a hand-held radio. They both run on AAA batteries, so no risk of discovering that the battery isn't charged when you need it (one of my selection criteria, in fact). The biggest risk with the handheld GPS is that I forget how to use it - the manual is in the plane but hopefully I could at least get a Direct To into it without rereading the whole manual.
I also have a backup electric AI with internal battery - not to mention that whenever I do currency flights they're invariably partial panel (when I fly IFR for real I have to stop and think about what to do with this funny blue-and- brown thing in the middle of the panel).
I guess as an engineer I just can't help being focussed on "what happens when it stops working"...
n5296s