I got an HTC Windows Phone 8X.
great phone, great OS. Unfortunately it wouldn’t work with my car bluetooth hands free kit (built in). A bit of investigation on the tinterweb and it seems the Windows 8 phones only have a limited number of bluetooth profiles hence the car connectivity issues and this has been a known issue since November 2012 so I doubt its going to get fixed any time soon or at all.
I managed to exchange it for an Iphone 4s at no extra cost (or refund ) at O2.
the Iphone works great in my car as did my Samsung galaxy and HTC desire and JCB tough phone and Motorola Defy and Blackberry whatever before it.
Avoid any windows 8 phone if you need hands free connectivity in your car and can’t be bothered with one of them “rep” ear piece things or unless you are sure it will work in your car.