Because I only pay £20 a month on o2 for the same minutes as their £40 tariff, plus unlimited data etc.... Which ever way you look at it the iPhone 4 will cost £750-850 so I may as well try and keep the best tariff I can.

Like I said I'm going to wait for the dust to settle. I see no point in swapping to Orange there is little/no cost advantage for me personally. Added to the fact I am totally happy with O2, their customer service is pretty amazing for a mobile operator.

Cheers

Cris.