For many years I have been a fan of the iA Writer app that is a streamlined and very fast text creation tool (as opposed to a bloated word proessor). The tool works seamously across the Mac, iPad, and iPhone and files are automatically available on all three Internet connected devices. This is also the only writing app I have found that works brilliantly on all three devices and screen sizes. The iPhone version is the only text creator I have found that really works well on the small screen of the iPhone.
A few months ago, iA introduced Writer Pro, a version that incorporates many new features while simultaneously retaining the simple to use, brilliant features of the original concept. If you are serious about writing text (as opposed to doing a fully formatted version at the time of the first draft), this is the app for you (unless you are stuck with a PC). In my experience, more creative and quality writing can be done more rapidly when you are not distracted by all of the formatting options floating around on the screen.
Writer Pro is simultaneously a 5-star app like iA Writer, a 5-Ferrari app, and a 5-tank app. The developer gets a 5-brain rating.
5+5+5+5 on a 5-point scale
Warning. This app has a steep learning curve (15 minutes). Unless you are willing to invest the 15 minutes you may not figure out how this new model of writing (with four stages you can jump between) enhances the creative process. On the other hand, you will recover the 15 minutes of exploration during your first 30 minutes of “real” use.