I paid for Hemmingway and have used to it to write all of my articles but it’s not without its downsides.
It’s incredibly buggy and that can annoying when you’re editing. For example, that little “Replace or omit” popup gets stuck on the screen and you can’t get rid of it. Sometimes it shows up randomly. Also once you get to around 3–5k words it gets really slow (on a Macbook Pro… 🤔)
I love the concept and I still use it to write, but it definitely has some flaws.