No problems with the built in sat nav here. Apart from the previously mentioned postcode entry and speed camera positions I think it works great. I have newish 09/10 maps so gives me few problems. Personally I think it sets the dash off great as well, looks . If I want speed camera postions for an unfamilar route I'll set my phone up, if I can be bothered.
Agree, wouldn't have spent £1600 on it but buying a second hand car I'd rather have it than not.