I have the 4. I bought the 5 a few months ago, but when my wife saw that white and shining thing I had to give it to her. I had it for about 2 minutes.
In a way it was the best of both worlds. I got the excitement of buying a new iPhone (an excitement that has felt less and less powerfully for each new iPhone mind you), and giving it to my wife made her extremely happy. She had an iPhone 3G.
I have to say that the only thing that I thought was great about the new iPhone was the weight, or rather lack of it.
Every other time I got an iPhone I felt it was a big upgrade, going from the original to the 3G to the 4 all felt like a lot of things were drastically better each time, but I couldn't say that about the 5.
It's a great phone, don't get me wrong, but it wasn't a problem going back to my 4.
If I was using the 3G, bought the 4 and then gave it a way and had to go back to using the 3G!
I mean that wouldn't happen, the difference would have been to big.
I would have gone straight out and bought a 4 for myself as well.
Just saying