I have been with O2 for years. Apart from being overcharged few years ago Im happy with the service & offers 02 provide. Connection is quite good, staff are mostly helpful.
I would also like to mention Nathanial working in Lewisham O2 branch for his outstanding customer service. My old phone broke down and I didnt get any connection. It was old so I decided to buy new phone. Nathanial was very helpful and informative, took his time and made an effort to explain me the options I have, specifics of the phones I was considering. He also helped to me to log into my google account as I couldnt access it from my old phone. Was very friendly, polite and professional.
I am very happy with the service I received and my new phone :)