On the other hand, it has been a heck of a satisfying phone experience for me, and being an unabashed geek and gadget fan technology is pretty much always of interest to me. The iPhone is fast, feature packed, and aside from all that has an iPod strapped to it (something that often gets forgotten). I've not bought a huge number of phones in my life, but after every phone I've bought I've had to endure "phone envy"; that is the desire to buy the next best thing that has come out. Windows Mobile was a particularly painful mobile phone experience, that I stupidly persisted with for various reasons. Since getting the iPhone 3GS though I've not had a jot of phone envy. At least until the iPhone 4 came out.
But IMO it doesn't have a big "wow" factor, despite what Apple and Steve Jobs will try and tell you.
Retina display - probably one of the best new features, and a nice-to-have, but not a game changer.
HD video recording / better camera - again, probably one of the best new features, nice-to-have, not a game changer.
Speed / Battery Life - You'd expect speed and battery life improvements in any tech upgrade, of a device that's pretty much the same shape and size. I don't remember Apple pushing values for the speed increase though, unlike the 100% figure quoted for the 3GS. I vaguely remember improved values for the battery, but to love the iPhone you also need to be fairly clinical about charging it (much the same for any PDA phone, and something I can live with).
FaceTime - awful feature name (that for some reason my brain translates into WankTime) and something I can't ever see myself using for more than novelty.
Multitasking - the reality of a PDA device is that you don't really need it, and the iPhone already does enough multitasking to make it usable e.g. email, text messaging and the phone all work in the background while you're doing something else - they'd have to or the iPhone would have been a dead duck from the start. The only apps I'd want to multitask are TomTom and CamerAlert, so that I can get SatNav *and* super accurate speed camera data. But for this to work I'd need sound from the CamerAlert app to appear while TomTom is running, and I don't believe that's how the iPhone's multitaskng will work. Practical upshot: no real use that I can see.
And now I'm struggling to think of any new features worth mentioning. Let me know if I've missed any.
But thanks to O2 and some sensible customer satisfaction/service decisions I can upgrade to the iPhone 4 for 100 squids. And I suspect I'd be stupid not to, bearing in mind the cost of a new phone, and that I get to keep my 3GS (which is worth almost 3x the upgrade price, but I suspect will be worth substantially less after June 24th).
The question is whether I'll be standing outside an O2 shop in the somewhat wee hours again, on June 24th. Perhaps I'll just opt for the by-post option this time.