You get the full basic set (d2, d4, d6, d8, d10, d12, d20, d100) all on one screen, with portrait and landscape support. A great option if you're a DM and your device has a kickstand.
Tap to roll. No funny business.
Most dice apps are needlessly obtuse "dice simulators." Even the ones with legitimately useful features are far less convenient than just rolling actual dice. The ethos of Dieroller is elegance. While future releases will add features such as multiple dice, calculation, n-sided dice, and (limited) themeing options, it will always hold fast to the original ethos. No superfluous "roll dice" button. No submenus, checkboxes, or skeuomorphic gestures, and nothing flinging around the screen.