When comparing Focused vs Letterspace, the Slant community recommends Focused for most people. In the question“What are the best Markdown editors for OS X?” Focused is ranked 30th while Letterspace is ranked 32nd. The most important reason people chose Focused is:
Focused's interface is quite minimalistic and allows you to focus on the writing and the writing only. There's nothing that may distract the user.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Distraction free writing experience
Focused's interface is quite minimalistic and allows you to focus on the writing and the writing only. There's nothing that may distract the user.
Pro Integrated Markdown viewer
You won't need an additional app to preview generated content.
Pro Stress-free writing
Very uncomplicated. Creates a stress free writing environment.
Pro Comes from a good stable
Developer has produced other well-designed and stable apps.
Pro Full featured iOS app
This was a iOS first app and that is clear. Great swipe bar interface on iOS.
Pro Simple, yet powerful interface
Keyboard shortcuts for basic text formatting. A few theme options. Full screen mode and swipe gestures.
Pro @mentions and #tags for easy organization
Pro Advanced Markdown support
Features Markdown support that many other text editors don't; such as Todo's ( -[x] ) and Strikethrough.
Cons
Con Might be abandoned
There has not been any update for quite some time.

Con Clunky interface
The interface is somewhat clunky and using it just isn't all that enjoyable.
Con Cannot publish directly to wordpress or other blogging platforms
Con No footnotes support
Doesn't handle MultiMarkdown footnotes well - or at all.
Con The "music" won't be to everyone's tastes
Focused uses various soundtracks to keep the user focused on the writing. But these soundtracks are built-in and may not be liked by everyone.
Con No in-app Markdown preview
You can export to PDF or HTML with formatting, but no preview in the Mac app.
