This is the best update the app has seen in its entire history: it's all about polish, thoughtful interaction refinements, and providing tools in a way that isn't distracting or overwhelming.
It remains the best blank canvas for plain text that money can buy.
I have used it since basically version 1 before it was iA Writer Pro. I fell in love with its minimal design and neat markdown support. It also helped me a lot in learning the markdown intricacies. After it released version 4 with image/file inclusions I knew that I'll be using this editor in long years to come.
Writer does something that's hard to put into words, but it just really helps me write. It gives me space, room to breathe and think. I always use focus mode. I've recently started using night mode as well. Sounds silly but its like a trigger now, I open Writer and its just easier to get out, what's in my head. I've been using the mac version for years. I didn't think I'd use the phone version as much initially, but I've found it to have the same effect as the mac version, it gives me a space to deposit thoughts as and when they strike and then expand on them later. I used to email myself lots of notes, which was messy. Writer shares everything across devices, so more of my thoughts actually get completed now and turned into writing I can use. I'm excited to make stuff with this latest version.