I've been with Three since 2003/4 after having tried O2 and Vodaphone, Orange etc. Their service has only every got cheaper for me every year. I started off at £150 per month, now down to £14 and can reduce that next contract.
Signals have always been worse inside a building compared to other operators but I think that was because they used a higher frequency signal - not everyone can have the lower bands. When I had no signal in one house I bought an amplifier. Now in this house , if there is a poor signal it auto switches to calls over wifi.
Combined with BT broadband (with their 5 million + hotspots) the service has been excellent.
No provider gives everything for nothing with the best service and the technology has it's black holes, poor reception near hills, inside buildings etc but instead of moaning I always find a way of making it very useful.
I've lived in Northumberland, Bedfordshire and now Lincolnshire - all very rural and the mobile broadband I get has always seemed as good as anyone else's and often better. If I need better signal I just move a street or two in 5 minutes and I have wifi, or of course lean by 43.2 degrees and get a signal.
The fact is, every operator gets slagged off, every operator advertises they're the best but as we all know mobile phone signals are iffy often, all over the place so just accept it and get around the problem with wifi.
I really don't understand why half the people here will pay £1000 for an iPhone and then quibble about £20 a month to make it work. So what if the bill goes up by 4%, you just accepted a 50% price rise for the phone. You can avoid all phone charges by using other free messaging services. I had a block put on my account so that my phone will not spend any more money than the monthly amount.
As techie people we are all used to fiddling about to get technology and software to work, after all that's what a lot of us do to earn money so just do it for the phone. Simples. It's modern life, nothing is perfect, everything goes up in price, everyone rips you off, every gadget goes wrong...get around it and enjoy life :)