I have had no problems with O2 what so ever, excellent signal coverage. Value for money is excellent when using bolt ons. Customer services have been more than helpful, I'm always able to get straight through. Had new sim requested and got it the next day! Always very friendly and willing to help! I recommend O2 to anyone who wants to save money!!
I have not yet found a place I can't get signal. They are a lot cheaper than the other networks. I now get 10% of all the money I spent that month back from 02.
The customer service could be better though. Sometimes takes a while to even speak to someone.
I've been with O2 for two years and have never had any problems in that time, whenever I call customer services the staff are always really helpful, patient and friendly. I pay ?30 per month and get 1000 text messages and 400 free minutes. Absolute Bargain!
In my experience they've got good customer service. But I have had problems with reception in some areas, especially where I live. But overall they provide a very good service. I've been with them for the past 5 years.