[new cruelty]

I've owned a few in the past few years. I liked using the Journada most. However, inevitably they all ended up gathering dust on my desk.

I can see how productivity would be affected. I think the ROI will be realized once the cell phone and pda merge into a light weight product (which is already available in various forms). Ideally, I would like to see such a device in the form of eye glasses, wherein the User can operate using eye movement and hand motions, though that might look a bit odd to the casual observer.

[eno_]

the ROI will be realized once the cell phone and pda merge into a light weight product (which is already available in various forms

Almost all new phones are fairly powerful PDAs. It's just that the UIs suck and the integration (synchronization with your PC) they COULD be doing over the GPRS or 1xRTT data networking sucks or is non-existent. But it doesn't take much software to keep your address book, calendar, and read and send e-mail. The PDA value proposition is too small. Phones will win.