I have tried so many writing apps. I write thousands of words every day, using my iPad exclusively, and I need a great word-processing app, as well as a great distractionless writing space, and a great note-keeping app. This one is perfect for all three. I use it for long pieces, for notes and snippets of ideas I want to save for later, for comments and posts on social sites and blogs, for journaling, and for saving interesting links that I might reference in my work.
It syncs perfectly with my iPhone, so I can work on the go. The ability to download themes is great. I love using the "Private Dancer" theme for writing in public, no one can read over my shoulder. It works reliably and I have never lost any writing to crashes or sync failures. Highly recommended.