My advice is the HFP cradle. In a few posts time you'll be able to get a 5% discount from
www.comandonline.co.uk so PM alfie, and if no reply, then PM me for a discount code
If you're heart is set on the SAP cradle, then I suggest a new Nokia phone.
Just to summarise again the differences: -
SAP cradle is a phone in itself, it uses a bluetooth 'profile' called SAP to get the ID of the SIM in your phone and then uses that, so it then (a) uses the car's external aerial (b) doesnt use battery so fast on the real phone (c) you can do SMS. SAP is not supported by most manafacturers. It only really works with Nokia and a couple of Siemens phones. Windows mobile 6.0 claims to support SAP but it doesnt work. You have to tell it specifically to download the phonebook from he phone (by dialing 0000), as it has to switch from SAP to someother profile to do it. SAP cradle also handles multipe numbers per phonebook contact nicely by suffixing them with /W /H /M for work/home/mobile numbers held against the contact. SAP can also take a sim in it, then bluetooth is turned off and it behaves just like a fixed phone. SAP is a nice shiny looking device.
HFP cradle just looks like a headset to the phone, although it has the feature to download the phonebook automatically (using a different bluetooth profile) - the phone is doing transmit/receive, which is in the car, so if you have infra-red reflecting glass this is bad news for reception. HFP cradle supports more phones (such as blackberry). It doesnt work on older D2B cars as the other party gets an echo on a lot of phones, and its phonebook download is not as good as SAP - often only the default number for a give contact is downloaded, with some phones no download at all. Its also retail £100 cheaper than SAP. HFP is a small black box.
Both systems pair with upto 3 phones - but only one at a time.
Hope that helps
Regards
Richard