Mason,

The TM-510 does have a PDA function...sort of. You can store 200 contacts with each 5 numbers, and it also has a calendar and appointment book. I am still waiting for the release of the (free) software that allows me to sync with Outlook.

I have used several PDAs over time, including Sharp Wizards, Zaurus, Palm and Windows CE. But since I mostly use a PDA for lookup, I have been quite happy with my REX for the last 2 years.

And now it looks like my phone can take over those simple PDA functions as well :-)