Apple I-phone 3gs Overview

There's a reason why Apple called this the iPhone 3GS for Speed and not the 3GC for "compass" or 3GV for "video recording." Speed is the central upgrade here, and probably is the single biggest reason you would upgrade to a 3GS from a 3G. And if you're coming in as a virgin iPhone user, there's definitely no question: The 3GS is worth an extra $100.

That declaration may be weird to most of us since we usually look for features, and not specs, when we're evaluating phones—and iPhone 3GS doesn't blow us out in the feature department. Instead, it's like getting a bigger TV or a faster car. Your old machine works just fine, but once you've tried the new one for a week, you'll never want to go back, even if it costs you a little extra.

from the outside the 3GS is exactly the same as the 3G. It's slightly heavier and has glossy text on the back, but if Steve Jobs whipped one out in public before it was announced, you wouldn't have been able to tell the difference.

By holding the 3GS next to the 3G, you'll notice that the screen is slightly more reflective because of the new fingerprint resistant oleophobic coating. It even has a little bit of a rainbow effect if you reflect a monitor with it. Surprisingly, the coating actually works in preventing a good deal of fingerprints and face grease, and it allows the phone to still be smooth and usable even if there are fingerprints on the surface.

The two phones may look similar in how much finger and face grease are on the screen, but the iPhone 3GS is still usable and doesn't have the problem of "sticking" in certain areas that are slightly greasier. It's also easier to clean just by wiping on your shirt. The glass treatment won't eliminate smudging from your bodily secretions altogether, but it's a very useful improvement for something you're touching all the time.

the iPhone 3G will still run most of the games for the near future. That 40 million unit potential market of iPhone/iPod Touch devices is too big to just ignore and put out an app just for 3GS phones, so your old phone will still be able to keep up. But developers are like alcoholics. If you put more system resources in front of them, they can't help but use all of it just because they can. Also, they drink a lot.
Apple hates to emphasize specs in products like the iPhone 3GS, but even they couldn't resist bragging about the speed boost. That S is there for a reason.
The 3GS also has a 3-megapixel camera, adding auto focus and video recording. You even get an interface that lets you tap on a section of the screen that you want to focus on and the phone will automatically adjust the focus to that point in space.