I've been using XP Pro exclusively with my TSU9600 and PEP. No specific problems regarding XP Pro that I'm aware of. I do have problems with XP Pro detecting the remote quite often. I'd say at least once every week or two. A simple undock, remote reset, redock always does the trick however, and like I said earlier, there was the one time I had to do a full firmware update to get things working again.

Interesting note on the full firmware update....
Prior to running the full firmware update it was taking a very long time for me to download my XCF to the remote. We are talking 6 minutes or more here. Seemed way too long to me even with my XCF being around 36 megs which leaves less than 1% free memory in the remote. Well after running the full firmware update I was pleasantly suprised to find my XCF downloading to the remote in under 3 minutes. It's been a couple months now since running the full firmware update and downloads are still taking just under 3 minutes thankfully.