When comparing StackEdit vs Memosnag, the Slant community recommends StackEdit for most people. In the question“What is the best cross-platform note-taking app?” StackEdit is ranked 28th while Memosnag is ranked 63rd. 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.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
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 Supports various Markdown flavors
Supports standard Markdown and Markdown Extra.

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 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 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 Extremely simple and intuitive
The plugin is very easy to use. The social-media-like page layout makes it easy to navigate, while the drag-drop functionality, used to organize your content, is highly intuitive as an Evernote alternative.
Pro Automatic citations save time
Memosnag creates citations automatically, which saves the user a ton of time.
Pro Lets you save pretty much everything online
Unlike other clippers, memosnag allows you to save pretty much everything online in one simple click. That includes images, YouTube videos, websites, etc, which makes it a good Evernote alternative in this area.
Cons
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 Comments can only be written in Latin script
You cannot add comments in Cyrillic, or Hebrew, or any language that uses symbols other than the Latin alphabet.
Con Does not work well for note taking
Memosnag is only for saving/sharing content you've found online (sites, videos, etc.).
