I will agree that the Zaurus is more like a micro laptop than a standard PDA thanks to the Linux Operating System. That was one of the main reasons why I bought it, because it seemed to be significantly more flexible than a Palm or a PocketPC.
I think the only things that have let the Zaurus down are:
Lack of Sharp's involvement in promoting the device and evolving it's applications, this is well documented, so I'll say no more.
The way that it's more niche than mainstream, again as as a result of the applications being more for more advance linux users than for the average everyday user.
However, for a two year old PDA, I've managed to keep mine in pretty good condition (partly thanks to buying a good case for it the second I got it) and recently having abandoned the sharp roms for OZ, thanks to buying a wireless card for it and only being able to get it to work under OZ, I'm finding I'm using it more and more again.
If OE does get up a head of steam, perhaps that will re-ignite the developer community behind linux hand helds, which you never know, might reawaken demand for Zaurii....
However, I do personally think we'll end up using other devices that are more readily available globally. When my Z5500 does die through old age, I won't be buying another Zaurus, not even an import, unless it's really special!!