Personally, I think the upgrade from the 4S to the 5 was a minimal one. The screen is longer, yes, but not so much that its noticeable to the point that if you really weren't looking for the difference, you'd actually know. Things such as weight & speed? I seriously have never given THAT much notice to these two aspects, so it's hard for me to picture others doing so. (Besides, JUST HOW MUCH speed DO we need? We continue to measure the speed against the previous model--its not like we had a problem with the previous models' speed!!) iOS 6 from iOS 5 was a nice change, however--again, not a major change, but the new capabilities are nice. I'd say, if you want to say that you have the 5 and no longer have the four, then the upgrade is for you. If not, you're good with the 4S!