
Originally Posted by
Ferral
He will have been trying to tell you about what are known as MVNO. The thing is though 3 and O2 are not MVNO's they are full first party native providers. Now BT & Virgin are MVNO's as they get their airtime (or rent it if you like) by using a network that isn't theirs in both these cases EE, GiffGaff use O2, Voxi use Vodafone and Sky I believe use O2.
So it sounds like he was pushing the hard sell on you by scaring you into thinking you will be worse off on a different network.
Personal experience is that 3 weren't the best, they have got way better though over the past 10 year or so and now a decent competitor. O2 are also decent but I found them to be more expensive when I was still working for them. O2 (aka telefonica (Spanish) much like Orange was Hutchinson Telecom (Dutch)) suddenly appeared overnight as BT used to have their own dedicated mobile network late 90's early 00's with all the infrastructure setup, they sold it of to telefonica and O2 had a huge ready to go network there and then for them to launch well. Mad to think BT now have to get their airtime from another provider!