i upgraded from my iPhone 2G, and what a good idea. The performance things bumming me out about my original iphone were not so much 2G v 3G related, but some things just seemed to take forever:
- stopping a page load in Safari
- getting to the point where i could open a new page in Safari
- switching apps
- connecting to the Exchange server at work
- updating the emails from said Exchange server
- opening the camera app and taking the first pic
... and so on. Good god does the 3GS fix all that and more. I hadn't even realized how bothered I was by how long the 2G took to connect to my home wifi node.
so far, the 3G connection speed has been good, somehow better than the gf's non-S 3G connection speed. the camera, though not great, is far superior (the very first pic I took is above; taken in low-light conditions). the maps app handles zooming and scrolling much better. simply put, everything is faster.
I may have waited too long, or jumped the gun, as the first reports of the next-gen iphone "in the wild" have surfaced. And to get the pricing, I did have to re-up for a 2 year contract. But I reckon I'll be happy with this for that duration. sweet!
update: only downside is the battery life has suffered, in an obvious manner.