Not a lot.
+ The Good:
Thinner and lighter (it’s not thinnest smartphone)
A6 (I’m quite sure its not A15 architecture)
1GB RAM (tbc)
720p front facing camera
More improved touchscreen and display(wont work with gloves on, unlike Lumia 920)
And most important they finally got rid of stupid glass.
No Inductive Charging
No micro SD
No micro USB (It’s mandatory in Europe and should be world over)
No new software gimmicks
Same battery life
3 years old design
That new adapter for old port is huge (and will cost extra)
Still no FM Radio
Still stuck with iTunes
Still no file transfer over Bluetooth or USB Mass Storage mode
My subjective opinion:
iOS feels very dated compared to Windows Phone and the latest Android. This can be improved if you jailbreak it. Camera could be better (look at Nokia 920!). It’s difficult to get excited over a 4″ screen and LTE at this stage in the game. When the iPhone first came out it was unparalleled. But with the level of innovation going on in the industry with the Windows Phone 8 and Android Jelly Bean devices, this looks boring. I’m kind of surprised they actually designed iPhone5 to match rumors leaked at the time 4S was released. Good job Apple, now you could bring your design team back from vacation.
Best iPhone yet? Yes.
Best smartphone on the market? Nope.
Ahem… Apple didn’t deliver, they merely “caught up”.