I'm on with 3 and was going to switch to T Mobile flext 35 @30squid a month if you do it online.
3 offered to give me a new phone, match the tariff and deduct 25% so getting 180-00 credit for £26-25.
Started off with orange in the early days but found too many dead spots,3 service has improved,but to be honest no network is perfect.
John