Can someone explain in layman's terms how this is any better from an app like the Hemmingway Editor [0]? Both analyses the text and makes suggestions to make it better.
See our discussion of this at http://proselint.com/approach/. I'll note that we do not consider Proselint a complete product — it's in its earliest stages, perhaps at 2% of its final capacity. That number has steadily decreased as we learn more, which we take to be a good sign.
Hemingway is an editor while Proselint is a tool. The latter can be integrated in any editor. That’s the main reason I ditched Hemingway (the editor) because I couldn’t just copy/paste text in it to get some suggestions.