One of the most interesting things about Polarr is that you can set up the interface however you like. Just tap any of the icons in the various toolbars to move or place it wherever you want. In this way, you can properly customize the interface to adjust to the tools you use most frequently.
In terms of the tools, Polarr also notably stands out: you can correct the contrast, brightness, and saturation; subtly change the lighting; adjust the sharpness, perspective, and distortion; apply color overlays; and even create your own custom filters. Yes, you can create and save your own filters.
Polarr is a photo-editing app that can deliver spectacular results. That said, you do need to dedicate a few minutes to figuring out how to use it properly, as it's got a lot of features.