When comparing StackEditPro vs Zettlr, the Slant community recommends Zettlr for most people. In the question“What are the best open source Markdown editors for UNIX-like systems?” Zettlr is ranked 9th while StackEditPro is ranked 21st. The most important reason people chose Zettlr is:
While many Markdown editors don't offer specific support for a certain type of workflow, or offer features for scientific workflows only, Zettlr offers features that help the writing process of journalists or researchers in the arts and humanities. It's a lot more text-focused than most editors.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Synchronize multiple devices
Pro Publish to many web services
Pro Free
Pro View table of contents and file tree at the same time
Pro Add links between documents
Pro Extract sections to new documents
Pro Rename/Renumber multiple files
Pro Text search all workspace files
Pro Synchronize multiple workspaces
Pro Focuses on writers
While many Markdown editors don't offer specific support for a certain type of workflow, or offer features for scientific workflows only, Zettlr offers features that help the writing process of journalists or researchers in the arts and humanities. It's a lot more text-focused than most editors.
Pro Citation support
While it supports a diverse range of syntax (chart, easy image insert, etc.) found in other editors, the great citation support made it possible to write real articles. Citation from Zotero and Mendeley can be inserted easily which is a huge plus.
Pro Almost perfect
This is the best option, still not perfect, there are some bugs like creating / editing tables and resizing images, but the PROS destroy the CONS, easy quotes, WYSIWYM , attachments tab (supports attaching and opening links to any file), table of contents, TAGs, easy hyperlink between files (same as citations), export to many formats (like Word, HTML5, PDF)...
Pro Renders math in-place through KaTex
Cons
Con Obtrusive, like someone WITH CAPS LOCK ON
Too loud, too much going on, and definitely an in-your-face sort of feeling.