Texts vs Letterspace
When comparing Texts vs Letterspace, the Slant community recommends Texts for most people. In the question“What are the best Markdown editors for OS X?” Texts is ranked 20th while Letterspace is ranked 32nd. The most important reason people chose Texts is:
Unfortunately, this is a global setting for save (it can open any dialect)
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Supports multiple Markdown dialects
Unfortunately, this is a global setting for save (it can open any dialect)

Pro Immediate Markdown rendering and preview
Texts immediately renders the formatted Markdown as you are typing it inside the text box. It's quite similar to a WYSIWYG editor.

Pro Imports and exports many formats
HTML, Word, TeX, PDF, ePUB, OPML.
Pro Works on Mac OS X and Windows
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 Overwrites standard Markdown
Editing a preexisting Markdown document overwrites standard markup in it (for example, interpreting headings marked with leading "#"s and rewriting them with a trailing underscore line), adds extra blank lines between all paragraphs, and adds extra spaces at the head of unordered-list items.
Con Spell checking is not activated by default
There's a built-in spell checker which is not activated by default and is quite hidden.
Con Limited choice of built-in themes
You can download the CSS for these themes and create your own, but would be nice to have more flavors (e.g. GitHub)
Con No word count in older versions
Word count is present in Texts 0.21, at least.
Con No in-app Markdown preview
You can export to PDF or HTML with formatting, but no preview in the Mac app.
