I’ve been with three for 5 years and I’ve had issues with them from day one, mind they have calmed down now to slight coverage issues only.
At first their customer service (phah) was shocking, now it’s excellent.
Their billing was appalling, now it’s excellent.
Their coverage was pants, now it’s a pair of bloomers flowing in the breeze, except in the South Downs where it’s none existent. 3G is sporadic all along the south coast, signals fine on H+ so calls and slow Internet’s fine, then you go through 3G hotspots so you get sporadic G coverage as you whiz by.
I’ve had the same issues as binners in London, again it’s a bit odd being in the Capital and not getting 3G.
Maps are a bit random coverage too in London, I stood under T57 in Broadgate looking for T57 and it said I should be ¼ mile down the road near London Wall.
So, coverage, depends where you are.
GPS, depends where you are..
I’m sticking with them though, think they’re the best of a rough lot.