What Network to use?

Hello there, Im a VERY basic user when it comes to mobile phones but I get bored very easily so change them alot. I recently got the N95 from O2 but had problems with 3 handsets, anytime I changed the shortcut keys the microphone wouldnt work! A very basic change to a phone so it was a bit of a mystery as to what caused the fault, the O2 shop were very helpful and changed it as it was only a few days old, they gave me another 1 which lasted less than a day - same problem, another change later and the thing kept freezing when there was no applications open! O2 shop said that unfortunatley they'd run out of stock as quite a few had been brought back through different faults. I was very impressed with the quality of the phone, the camera and video was the big selling point to me, I wont actually need the Sat Nav or some of the more compicated applications (which is where the BASIC user comes in!). Ive been to nearly all the mobile shops in my town and nearly all of them say theyve not heard of any problems with this model - Carphone Warehouse were the pushiest insisting theirs are perfect! Orange are offering quite a good suitable tariff for me but what Im asking you guys is whether they are to be trusted? Everyone has good and bad experiences but O2 say theyve had a "bad batch" so what about Orange? I would appreciate any advice you can offer me. Thanks to all in advance.