Still have my iPhone 4, but went to the Apple store to check out the iPhone 5. It sounded great, but not too great, but I was wrong.
The first thing you notice is how light it is. It makes the iPhone 4 seem heavy, but it still feels well built and solid. And the mostly metal back is much better than the glass iPhone 4 and 4S. The phone is thinner, and lighter, and taller.
The taller screen looks better even at the same resolution. And the bigger screen is just better. Wide screen shows look great and having an extra row of apps on every screen is fantastic.
And the lightning connector is impressively small. Still if it is not faster, it sucks to make every previous accessory either incompatible or have to work with an adapter.
if all of the speed tests are true, this is a really impressive phone. I so want one! Ha!