Works flawlessly for me w/Win XP Pro and Office XP. Using PCCARD to sync. Haven't tried Serial cradle, but hear it works.
USB cradle could be problemmatic - make sure you follow install instructions carefully in any case. There are several troubleshooting approaches for using the USB cradle w/Win XP on the operating System Information page on my site - review them before you start if you are going to use a USB cradle on XP.
The only exception from the install instructions for me was that after installing all the software, I simply inserted the REX and the proper drivers were installed automatically, and I was off and syncing. Didn't need/want to run REX Tools as I already had data on the REX and wasn't starting "fresh."
