I have been with Three since March this year, using the phones (3g) in Yeovil (When signal quality has allowed).
My experience has been that the Three Mobile, (3 Mobile) network coverage in the Yeovil area is poor. I have had 2 x INQ1 phones which I have been advised work as well as any other model, time will tell as I am now using a different model.
My other phones are on O2 (Tesco PAYG Mobile) and Vodafone and have never lost a signal in the Yeovil area or as I have travelled around unlike Three.
I have called Three customer services numerous times and have found the process frustrating and costly in time (need to have your mobile on the charger).
I have been looking for reviews on the Three Mobile Network, I have listed some below:-
Three's own map of coverage in yeovil shows that your phone may only work outside
Three have actually admitted that the reception on INQ1 phones is not as good as it ought to be (this cause the phone to work harder and discharge the battery). INQ are bringing out a new version of the INQ phone some time soon.