A few weeks ago I switched my main personal number to giffgaff and today I ported our third family number to giffgaff. Why? For the first time I'd found a mobile operator that seemed to reflect my values and requirements. Simplicity, no ridiculously long contracts (these now seem to be the norm elsewhere), top quality customer service and great pricing. Prepay services are not normally good value for heavy users but giffgaff has addressed that problem by allowing customers to buy 'goody bags' that provide the usual value bundles of calls, texts and data but in a prepay environment.
gifgaff doesn't sell handsets, hence no need for long contract, subsidised handset purchases. You just put a giffgaff SIM in an existing unlocked handset and off you go. Having done the maths on buying a subsidised, SIM locked, contract iPhone from one of the usual suspects against a SIM free iPhone from Apple with a giffgaff bundle there doesn't seem to be much in it. Factor in the benefits of no contract and no SIM lock if you want to use another network here or overseas and suddenly the idea of a contract handset purchase looks a lot less attractive.
If you are thinking about giffgaff their goody bags are half price until the end of August so seriously good value at the moment. And if you want to just give giffgaff a go or put a low spending member of the family on giffgaff, calls are 8p a minute and texts 4p. Bargain!
giffgaff uses the O2 network (it's actually owned by O2 but operates as a separate business) so if O2 coverage works for you, giffgaff will be fine.