Iphone from North America

Im from the UK and looking to move to Noth America soon, so am not sure if I should get the iphone 4s from the UK or US or Canada. It will be cheaper in North America but I know there is a difference between the networks that we use here and there, GSM and CDMA.

Will all the iphone 4s work with both GSM and CDMA network or is there a specific one that I should get, such as directly from a mobile operator or apple.

Also wanted to get the Ipad 2 but wifi only, would that have a problem if I bought that back over to the UK. I dont think it will but will software updates and warranty be ok?

The iPhone 4 S is a "world phone" and can switch back and forth between GSM and CDMA. It will work in the UK. If you bought it from say, Verizon, the Verizon warranty should be good in the UK as long as Verizon is there. If you get an AppleCare+ warranty, then the warranty is good at any apple store. Same for the iPad 2.

If you are moving permanently (or at least for a couple of years) to the U.S., it would be cheaper to get your iPhone in the U.S. due to the exchange rate and the very short contracts (two years). Canada has basically the same cost but longer contracts (three years) and the plans are not quite as inexpensive. UK plans are considerably cheaper at the basic level last I looked, but wherever you end up you have to get a plan there.

If I were you I'd buy a completely unlocked iPhone in the US (where it is cheapest) and then sign up with whatever providers are available to you where you end up. In Canada, I think Bell and Fido are the best options; in the U.S. I always felt AT&T was very good to me BUT there are some parts of the country where AT&T is *not* the best option.

Thanks for your replies guys. I will get an unlocked one from Canada, but I saw that it will only work on GSM networks and not on CDMA, any ideas why?

Is it also possible to do engraving at apple stores?