Well I had a play with one today, and first impressions - I think I much prefer it over the 3G I currently have!

I had the original (metal back) iPhone before getting a 3G last year (didn't bother going to the 3GS, as I was offered a 3G for half the price lol) and instantly wasn't as happy with the 3G as I was the 2G. Obviously I much prefer the faster speed of both the cellular data and the phone in general, and the display, and speaker/mic on the 3G are better, but I was never happy with how it felt in my hand - the 2G was slimmer and thinner (width) than the 3G and 3GS, and I've never liked the curved plastic back on the 3G/S either - the flat metal back of the 2G was much better IMO.

So with the 4, I'm loving it's flat back. I'm loving it's slimmer, and I think it's a tiny bit tinner (width) but actually a tiny bit taller. The display is AWESOME! It's like the first time going from a CRT monitor to a TFT lol. Text on it looks fantastic, the icons look fantastic, pictures, video, all looks really good. Very impressed. Side by side comparrison loading TVcatchup in safari, selecting a channel and getting it to play between my 3G and the 4 - the 4 won hands down. And thats over wifi so as to eliminate cellular data speeds between networks. Same with loading up a webpage from scratch - used Apple's US site, twice as quick from start to finish on the 4 than my 3G. So that shows the internal spec is much better and faster than the 3G's cpu/ram...

So all in all, once the problems have been ironed out, and T-Mobile sort me out with a deal on getting one, I'll deffo get one. Probably only the 16gb (I don't keep music on my 16gb 3G so not fussed about space) and deffo the black one, as the white looks fucking GASH!