IO540 - yes, albeit only a few of each. I've flown myself around Southern England and Northern France, with various "handheld" GPS (not CAA approved), and with a GNS430 (approved for BRNAV).
The handhelds have all "lost signal" on me at some point - and with no warning or RAIM indication. The 430 has never so much as sneezed.
I can't comment on the build quality of either, because I've never had them open. The GPS3Pilot (my last handheld) is a very nice, solid, quality feeling bit of kit and I like it. But I like the GNS430 a whole lot better.
I carry an Icom for the day I have a power failure. It has the VOR facility, so in theory I could navigate with it, but don't much fancy the exercise. I've never used it in anger, although it does get used frequently for calling for start clearance.
The GNS430 is indeed not approved in the UK for IFR approaches etc - but it still provides a splendid backup to the ADF when on a procedure
