If anything, it'll probably be the iPhone 4S to be honest. Yeah, the screen might be a tad bit bigger, have a better camera, the new A5 processor, and maybe a redesigned antenna, but as far as functionality and features I don't think it'll be much different.
I don't think you can go wrong with either. If it were me, I'd prolly wait the 6 months max to get the newer one, but it's your call.
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