I have a new SE W900i (3G version of the W800i) on Vodafone UK and it works pretty well with my E90. Pairs and transfers phone numbers fine. Only issue appears to be that if you disconnect or turn off the phone while in the car, the address book function gets confused, and won't work. Re-starts fine next time.
Nice phone, although only available in white for now, which is a bit girly. Black ones due 'sometime.'