When comparing Markdown Edit vs Boostnote, the Slant community recommends Boostnote for most people. In the question“What are the best open source Markdown editors for UNIX-like systems?” Boostnote is ranked 16th while Markdown Edit is ranked 25th. The most important reason people chose Boostnote is:
Supports Windows, macOS and Linux.
Specs
Ranked in these QuestionsQuestion Ranking
Pros

Pro Free and open source
Licensed under MIT.
Pro Real-time HTML preview with synchronized scrolling
Markdown Edit is split in two panes. One pane is used for writing Markdown, the other shows the rendered HTML as it's written.
Pro Cross platform support
Supports Windows, macOS and Linux.
Pro Markdown support
Pro Free
Pro Open source
See here.
Pro Great for developers
Boostnote is great for developers looking to take programming notes with code snippets and such.
Pro Supports code snippets and syntax highlighting
Boostnote has the ability to store code snippets and comes with syntax highlighting out of the box, supporting many languages.
Pro Works offline
Boostnote doesn't require an internet connection to work. You can write notes offline and sync later.
Pro Global search, tag feature
Pro Comes with many themes
Boostnote comes with many themes out of the box, most of which are popular themes and color schemes for code editors: e.g. 3024, base16, solarized, tomorrow.
Pro vim/emacs key bindings available
Boostnote supports vim/emacs key bindings. If you're a developer familiar with either of them, navigation should be easy to pick up.
Cons
Con Dead project
Con Covers taskbar when maximised
When maximised, the window covers the taskbar completely even when the taskbar is set to be on top of other windows.
Con Does not support pasting images from the clipboard (unless online)
This editor boasts that it's a desktop (i.e. offline) markdown editor where you can copy and paste images directly in the editor which is a feature that many other markdown editors struggle to implement. Unfortunately this is misleading, since the only way to paste an image in the editor is to be online. If, like many of us out there, you want to work offline, this feature will be broken as it requires an internet connection, which is weird for an editor that boasts being a desktop app!!
Con Some of the features are not consistent
Con Must use third-party service for sync-ing (Dropbox, etc.)
Boostnote does not have sync-ing capabilities and relies on third-party services to fulfil notes storage. There are additional steps involved to set this up.
Con Can't work in "real" offline mode
Con Very poor syncing
Data loss may occur on syncing.
