Physically, the device in-hand doesn't feel that much of a greater difference. Though it is slightly better than the flimsy design of the Nexus One. The phone uses light plastic as it's main shell component, instead of metal. The screen is a super AMOLED screen and bright, the phone is light and when held, it fits perfectly in your hand. The back battery case is curved at a slight angle, thus making it a better feel when held.

The battery life on the Nexus S may run out fast if you have the screen on for extraneous amounts of time because of the super AMOLED screen (VERY BRIGHT AND CLEAR/CRISP). You may or may not need to carry a spare battery depending on personal usage and what not. Though I am pretty confident that the battery shipped with your Nexus S is in tip top shape for high usage time.

The camera is pretty decent, it comes with Android 2.3 (Gingerbread) with a better and renewed camera application/software. Features include auto focus and what not, but it does lack a feature of zoom out of third party applications in the App Market. It does have both a front and back camera, but the front camera sits at 2MP while the back at 5MP.

The keys on the bottom of the Nexus S from left to right are the back button, menu button, search button, and the home button. They aren't physical buttons but rather touch buttons (built into the screen's touchscreen itself, PRETTY NEAT). It's actually not quirky at all like one would think since it's not physically touchable, but there's no lag and it works like the screen's touchscreen. Quick, sensitive, and fast response time.

The device is defiantly faster than it's former part (Nexus One). First off, it has a faster processor and better specs in general. Also the Gingerbread OS is much faster than it's older counterparts as well with all the bug fixes Google has been throwing out constantly to all current devices.

Last but not least, compared to iOS devices being the iPhones, the Gingerbread OS compares pretty well. The Android OS' have more customization though in terms of making your own roms (the OS), customizing the rom completely removing and adding special self-made or community made features. The iPhone though can run themes in Winterboard and whatnot but that's about it.