When comparing StackEdit vs Caret, the Slant community recommends StackEdit for most people. In the question“What are the best Markdown editors for OS X?” StackEdit is ranked 1st while Caret is ranked 19th. The most important reason people chose StackEdit is:
StackEdit works within your browser. You need internet access to connect to the website, but once it's loaded, the site does not require an internet connection - you will be able to edit and save files locally. Additionally, you can use [Fluid](http://fluidapp.com) to turn it into a native desktop application.
Ranked in these QuestionsQuestion Ranking
Pro Works online and offline
StackEdit works within your browser. You need internet access to connect to the website, but once it's loaded, the site does not require an internet connection - you will be able to edit and save files locally. Additionally, you can use Fluid to turn it into a native desktop application.
Pro No need to install additional software
StackEdit works directly from the browser, there's no need to install additional software as long as you have a web browser installed on your computer.
Pro Real-time preview
The preview shows in a collapsible pane on the right hand side.
Pro Instant publishing
StackEdit allows pushing a document directly to a list of publishing or file storage platforms or any SSH server.
Pro Supports various Markdown flavors
Supports standard Markdown and Markdown Extra.
Pro Multiple export options
Can export to .txt, .html and .pdf.
Pro Syncs via Dropbox and Drive
Files can be synchronized through Dropbox and Drive.
Pro Simple workflow
It is very easy to toggle between the preview and the editing windows. The black makes it a very focused writing environment. Of course it's possible to change that if needed.
Pro Great when in full-screen
Pro Single-pane hybrid interface
The single pane formats your MD as you write it but retains the markup so you can see what's going on.
Pro Has a heading navigator
Hit ⌘ G to see document titles in a hierarchical view, type and use the arrows to navigate.
Pro Has a file manager
Hit ⌘ T to browse current folder, navigate the file system and manage your files and folders, type to search, right click to create / move / rename / delete items.
Pro Supports multiple cursors / selections
Make ten changes at the same time, not one change ten times - lets you edit multiple lines at once, perform quick and selective find and replace, etc.
Pro Supports context commands
Hit "Enter" to fix spelling, convert list to ordered/unordered/task, convert reference link to inline, jump to reference link definition, jump to footnote definition, visit links, etc.
Pro Supports auto-completions
Auto-completion for paths of links and images, keywords in fenced code blocks, emoji, etc.
Pro Offers inline preview for LaTeX math expressions
Renders LaTeX math expressions as soon as you have finished writing them.
Pro Supports "select more" / "select less" commands
Hit ⌥ ↑ to extend the current selection to the next biggest element and ⌥ ↓ to shrink the selection.
Con Saves files in browser's local storage
Local storage is limited and if the browser crashes the text can be lost.
Con Cannot be accessed while being offline
Even though the editor itself works offline, you need internet access to open the website and the editor.
Con Lacks a good integrated spell checker
Uses the built-in browser spell checker which may not be as good as spell checkers other editors have. Depending on the browser, of course.
Con Publishing to GitHub requires giving write access to repos
In order to publish documents to GitHub, StackEdit requires writing access to your repos, something which many people may not be comfortable with.
Con Not free
No longer free, try and buy
Con The shortcuts don't toggle formatting
Pressing cmd+B, for example, will begin a bold segment of text, but pressing it again doesn't end that bold segment, it retroactively turns the boldness off. This interrupts writing flow tremendously.