As someone who has been an avid PDA-user since 1996 (ran through 4 Palms and 6 PocketPCs--actually wearing each of them out, not just change for change sake), I really believe the choice between the two boils down to what you need to do with your PDA. If your needs revolve around calendaring and an occasional file download/view/edit, then it's difficult to beat the simplicity and elegance of PalmOS. If you need to access Outlook, Word, Excel files on a regular basis and need real handwriting recognition (not letter recognition a la Graffiti, but genuine cursive-handwriting recognition a la Paragraph), then PocketPCs are your tools of choice.

Personally, I need to take extensive notes for work--and nothing beats jotting them down via a real handwriting recognition program running on PocketPC and having them directly sync-ed into Word files--whether via bluetooth, IR, WiFi or cable. Thus, my latest Pocket PC is the Dell Axim 50--where the ultra-fast ARM9-based Intel 624mhz processor converts my handwriting instantly and intelligently into text and where web-surfing is a breeze via built-in WiFi and the bright 480x640 screen.

Just my two cents. Cheers.