Samsung has announced the newest flagship in its Galaxy line of Android smartphones, the Galaxy S5. Physical differences between the S5 and last years S4 are minimal and subdued, but youll immediately notice the new dimpled removable rear cover. These subtle exterior changes make room for interesting features like a fingerprint and heart rate scanner on the front and back, respectively. The heart rate monitor is used by Samsungs much improved S Health app, which now contains an exercise coach, pedometer, and integration with other fitness apps.