Ulysses transforms your relationship to your writing software. Unlike a word processor, where you pick and futz and monkey around with formatting, fonts, and grid, Ulysses enables you to focus on the content, the words on the page. Formatting is handled simply through markdown, an easy to learn and easy to type structured markup; it takes minutes to learn. Meanwhile, templates enable you to export to PDF, ePUB, or .docx formats when you're ready to "publish."
It's extremely innovative sheets concept takes minutes to get used to, but then, again, transforms your thinking away from documents and towards components.
In addition, their sync to iPad and now iPhone is extremely well executed.
Currently the export formats, if you're a front end develop and you like to code, take more CSS know how then the average person would expect. A styles editor that created the CSS would be great.
There are no logical sections, yet: so formatting documents in different grid systems — two columns, one column, etc — isn't yet supported in a single document.
Before Ulysses, I strugged with writing in word processors: I was constantly distracted with styling the text, rather than writing the message. Now, I'm on focus, and on point, and far more productive.