Since leaving Fast4 Broadband due to the poor service I have no complaints against O2. They are a very reliable ISP and I have yet not even contacted technical support for any faults.
Regarding ping, i can now get pings of 45 when playing multiplayer games as opposed to fast4 where it was over 100.
The speed of serivce is excellent and to be honest theres no need to contact technical support since it is so reliable.
All I can say is that anyone who wants a good and excellent ISP should now switch to O2 and the price is also great.