there comes a time when every prospective consumer and analyst has to zoom out of the feature specifics and observe the overall demographics and purposes to buying a product.
As of now, the reason to buy an iPhone 3G S likely appeals to two groups - those who currently own an original iPhone or iPhone 3G, and those new buyers who are certainly convinced that this smartphone is for them but are determining whether the 3G S is really worth the additional price over the 3G at just $99. In all honesty, the decision really comes down to how productive the user can be with his or her time in a mobile environment.
For those with skilled learning habits of typing and texting over 60 words per minute, skimming through the specifics of web pages at ADHD speeds, or simply impatience, then the additional fluid responsiveness of the iPhone 3G S is definitely a must have for getting things done. For those users with more reclined habits, we could say the decision is yours truly.