They have a trial version for Windows and I downloaded iA Writer. I love the focus mode and syntax highlighting (it highlights noun, verb, adjectives, adverbs). Aside from these two feature, it is a very plain Markdown editor - so, my question is, why pay $30 for this when Obsidian provides the same interface for free for personal use?
But, I think maybe iA Writer for iOS/iPadOS will be a different story altogether.