Samsung has a bunch of new sensors scattered around the Galaxy S4's body, but the general layout of controls is largely unchanged.
Below the display you get the same three keys as on the Galaxy S III - capacitive Menu and Back buttons and a regular press Home key.
There's some extra functionality upon a long press too - the Menu key handles Google Now, while the Home key brings up the task switcher. Pressing and holding the back button brings the side bar for the Multi-window feature (if it's enabled) and if you click the home key twice the Samsung S voice virtual assistant kicks in.
Above the display we have the earpiece, as well as a bunch of sensors. The traditional ambient light and proximity sensors are joined by an IR gesture sensor, which enables the cool Air gestures in applications such as the web browser and music player. There's also a 2.1 megapixel front-facing camera for video-calls and a status LED up there.
The left side of the Samsung Galaxy S4 features the volume rocker, while the power/lock key is on the right. Unfortunately, despite the proper camera upgrade that the Galaxy S4 got, its flagship is missing a dedicated camera key.
The top of the Galaxy S4 features the 3.5mm audio jack, the secondary microphone and the IR blaster that allows you to use the smartphone as a remote control for your home appliances. There's also a remote control app with a pretty rich database preinstalled, so the functionality is available out of box.
The microUSB port at the bottom is used for both data connections and charging. Not only does it support USB host but it also comes with support for the new MHL 2.0, enabling 3D 1080p output and TV connections without an external power source. Previously you had to plug in your charger in the adapter as well, but the Galaxy S4 gets rid of that extra requirement.
The other thing of interest at the bottom is the primary microphone.
The back of the Samsung Galaxy S4 is where the 13 megapixel FullHD-capable camera lens is located. As on the Galaxy S III the LED flash is right beside it, but the loudspeaker grille has been moved to the bottom left edge of the device.
Removing the battery cover reveals the microSIM slot, the nicely upgraded 2600 mAh removable battery and the microSD card slot. We are yet to see what kind of difference the extra 500 mAh make, considering the higher resolution screen and the more power-hungry chipset.