so, my mum got one and I checked it out for a while and my conclusion is the following:
If you have an iPhone 4 or 4S, NEVER EVER upgrade.
I have an iPhone 4 and the 5 does not offer anything that would justify to spend the money. The software is the same, Everything that I would get is a camera that is a little better and Siri and I don't think that is worth several hundred pounds. And I have not found an app yet, that does not run smoothly on my iPhone4.
If you do not have an iPhone 4 or 4S, I would get the iPhone 5.
I love my iPhone4. I think it is a brilliant phone and I think the new one looks better, is obviously faster and bigger and has a better camera.