I'm on my second week of OS 5, and this should effectively kill all the silly complaining by Droid fanboys. A night and day improvement, and not much need to jailbreak your phone anymore. All the details are on Apple's website, and according to most sources this new OS will be available to the general public this fall.
Below is my review of the 16GB model that I purchased in September. Please note that this is strictly my opinion of the phone itself, I have no knowledge of this seller or the condition of the phones they sell. A word or advice however, if you're considering buying from this seller you need to contact them first to get details on the phone, warranty, and whats provided.
I had the 8GB 3G model and thought that was great, until I got a demo of the iPhone 4. Man is this version is light years ahead of the original model.
With a 1Ghz CPU, and 16GB of flash memory, this thing is a portable office/entertainment center par excellence. I've had this phone for 3 months without a single problem, the display is nice and sharp, the apps load very fast, and I now have over 130 apps to perform just about every duty you could possibly think of with absolutely no impact on performance. And on the AT&T 3G network, I average download speeds of around 1.8Mbps, and over 1M upload speeds....and how do I know that, cause I got an app that tells me that's how. BTW, the display is the equivalent of a 960x640 on your desktop (double the 3G model) so what you see is essentially a high res yield and page loads are superfast. And resident memory, after a full days use I just checked and still had 120Mb of Ram available. On the 3G model that number was usually down around 4Mb by the end of the work day and had to be refreshed.