I've got one of these: Sony : Support for XNV-L77BT | XNV-L77BT technical support
which I've had for about 2 years now.
The head unit interface is a bit dull and can be a bit clunky, but everything works well enough. The sound quality is good enough with the Boston Amp, but it's a whole different world with a new amp and speakers. The TomTom unit will fit in the glovebox and the HD traffic has saved me time on many occasions. TomTom keep updating the unit fairly regularly, probably twice a year and you can subscribe to their quarterly map updates. Sony appear to have abandoned the headunit itself though and have never provided a firmware upgrade since it was released.
I'm happy with it as a unit and it's still the only after market unit I've found with TomTom.
I had the original PAC adapter and it kept "forgetting" what the steering wheel buttons were configured for. The new integrated unit has been much better with less wiring.