Ranked in these QuestionsQuestion Ranking
Pro Real-time HTML Preview
MarkdownPad is split in two panes. One pane is used for writing Markdown, the other shows the rendered HTML as it's written.
Pro Allows customizing output
A custom CSS can be added to the rendered HTML to change the preview and output.
Con Abandoned project
Con Preview window crashes / does not update
Con Many features are disabled in the free version
Free version lacks features like auto-save, PDF export, Markdown tables among many others and can't be used commercially.