Hi I am usually based in America and have an iphone 5 with ATT. I'm now in England and will be for a fair bit of time so is it worth while unlocking my iPhone and will I have problems when I go back to America and back to my Att plan? Will there be problems when it comes time to trade in for the iphone 6? This service says that there won't be. Are they legit? http://www.officialiphoneunlock.co.uk/pricing.php Appreciate any advice.