The tech changes on this constantly. Generally nearer the exchange or the green cabinet ( assuming its on the fibre network ) the better.
Our last offices were rural and we'd experimented with satellite broadband (waste of time if it rains) best solution we found was bonded broadband, 4 broadband lines connected together with some special kit. Technically this doesn't exist though.
The amazing thing about all of this though is that when we were on the Nordkapp trip we managed to get 3G signals in tunnels at we're miles long in the middle of the countryside.
