Android: Though Android has no lack of photo editing apps, you often must choose between tons of features, and ease of use. Snaptastic stands apart as a powerful editor with an elegant UI.
The app comes with all the usual exposure and color adjustment sliders, as well as tools like crop and vignette, but the real draw here is the interface. Collapsible menus keep the photo preview front and center, while still labeling every tool and slider with its full name, rather than an obscure icon. Everything you need is both easy to find and easy to understand.
Snaptastic costs $4.18 in Google Play Store and is compatible with Android 2.2 and above. You can also sample the app with the free Snaptastic Lite, which watermarks your edited images.