I've tried it with three phones:

Treo 650 (unlocked/non-branded)
Blackberry 8700c (the new one/cingular)
Motorola v635 (unlockd/non-branded)

All three worked fine *except* I can't figure out how to upload the entire phone book on any of the three. I'm wondering if I'm doing something wrong. I can transfer one phone-book entry by one by one on the v635--> but that's not very helpful as I have over 400. Anyone figure out how to transfer an entire Motorola phone book?