Has anyone using 3g actually proved the accuracy of these maps ?

It seems to me that they are way to accurate - ie) the red blocks appear to go "round my house" (my neighbour is in the red - whereas I am limited to blue (std service)) - surely, they cannot be this dependant on individual buildings ?

http://maps.vodafone.co.uk/coverageviewer/web/default.aspx

Your house could be in the "shadow" of other buildings or hills. To be really accurate, the map would have to be three dimensional though because reception will usually be better upstairs than downstairs. The weather can also have a small effect as can the model of phone. In my view if you are considering investing a lot in a phone, you can get some friends round to check the reception of different networks and/or agree with whichever shop that you are using that it's ok to return the phone after a couple of days if the reception is not acceptable.