I don’t take nearly as many shots on my iPhone as I used to, but the ones that I do take are usually processed in Darkroom or RNI Films. I usually use the former because it streamlines the editing process so much, but there’s no denying that RNI films has some really gorgeous film filters of its own.
One thing that turns me off a lot of iOS photo editors are all the very fake extra effects that clutter up the actual filters. I don’t want to add fake sun flares, bokeh balls, or fake frames to my shots. I just want to be able to tweak the colours and tones, and then share them easily with other people. RNI Film simulations are based on real film stocks, and so you don’t have to deal with any fake extras being added to your images. What changes are the colours and tones. Once you have an image chosen, you can preview different films with a single tap. That tap can add a lot of pop to an image — so much so that I often don’t feel the need to spruce it up after that.