I would suggest an embedded OS, as in a proper GPS, is more reliable than either Pocket PC or Windoze mate!
While I don't disagree with what you are saying, or what IO540 is saying, some of us use a PDA solution, and are very happy with it. A PDA does have many advantages, including development.
For example my pda is about 2, maybe 3 years old. If I had purchased a Garmin at the time, I'd be looking at the great new models released since then and with all the feature that I don't have. But with PocketFMS, I just download the latest version and instantly have all th new features.
I also feel that the PocketFMS team are much closer to their customers than Garmin, in that they readily take suggestions and incorporate them into the next version.
Reliability was an issue when I first started using it 2-3 years ago, but that seems to be something that is simply a distant memory; at least for me.
But more than anything I would say it's biggest advantages are the layout and clarity of the display, the ability to customise it significantly, and the seamless integration with the PC. All preflight and post flight work can be done on a pc, and simply synced with the PDA.
The major disadvantage is the PDA's screen readability in strong sunlight. I find the Garmins screen to be more readable in direct sunlight. I would also trust the Garmin (Jeppesen) data to a much greater extent, but in the end I wouldn't trust either completely. My routes will always be planned on a paper chart, and the gps is simply to make sure I say on course.
dp