What's the new iPhone's USP?
I bought an iPhone 4S about six months ago and I think Siri sticks out as its USP.
I see very little reason to move from a 4S to the new model at the moment. Sure it has a bigger screen, but what else? A slightly better camera? A slightly faster processor? We'll still be able to upgrade to iOS6 on everything from the 3GS upwards (according to Wikipedia at least). Here in the UK, LTE is lost on us.
I can see lots people upgrading from a 3GS and possibly a 4 but not many from a 4S. Apart from those who just have to have one!