The Birdview isn't such a bad bit of kit if you buy it already fitted in a second hand car, as i did.
Couple of issues though.
1. NO POSTCODE SEARCH, really pain in the ass having to know the full address.
2. THE NAVIGATION AND TEXT ENTRY, slightly frustrating with that little joystick.
Definitely NOT worth buying one to fit, too expensive, Garmin or Tom Tom is your best bet.