Cymera is a photo application that can give a more fresh and dynamic 'look' to your photos, thanks to the huge number of possibilities including filters and 'lenses'.
Of course, once you have taken the photo there are more options available. More than twenty different filters let you give an artistic touch to your photographs, and a series of photo editing tools allow you to adjust brightness, correct red eye, improve colors, etc.
Cymera is a pretty good app that is even better than Instagram at editing and customization level, but it doesn't have an integrated social service.