When comparing nvALT vs typora, the Slant community recommends typora for most people. In the question“What are the best Markdown editors for OS X?” typora is ranked 1st while nvALT is ranked 10th. The most important reason people chose typora is:
Typora immediately renders what's typed on the screen in Markdown format. This helps users to have a better understanding of how their document is being formatted.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Powerful search syntax
nvALT has a simple text box at the top (similar to that of a web browser) and when you start typing inside it, nvALT immediately displays a drop-down box of all the notes that contain the text you are searching for. The more you type, the more the search is narrowed down.
Pro Lightweight
Pro Free

Pro MultiMarkdown 3 support
Has built-in support for MultiMarkdown 3.
Pro Powerful note-taking features
nvALT is not only used for simple text editing but also as a powerful tool for taking notes, TODOs, phone numbers and every other piece of information that can be stored in a plain-text file.
This is because nvALT is not designed only as a tool to write text, but also as a powerful search and organize tool for plain-text files.
Pro Right to Left support

Pro Live preview
Typora immediately renders what's typed on the screen in Markdown format. This helps users to have a better understanding of how their document is being formatted.

Pro Hybrid interface
The editor and preview dual-pane setup typical of desktop Markdown editors are gone; instead, a singular interface makes for a WYSIWYG experience. This streamlines the workflow and encourages direct manipulation.

Pro Support for LaTeX expressions
It supports LaTeX expressions, with an easy-to-use MaxJax panel.

Pro Syntax highlight for fenced codes
It supports GFM's code fences, with syntax highlight support for C/C++, java, etc.

Pro Custom theme support
Typora has clean yet beautiful built-in themes and allows for users to create new themes using CSS.

Pro Support for tables
It supports tables for Markdown Extra. And also provides a GUI to make it easy to insert and edit them.

Pro Inline images
It won't display image like 
, But shows the image content inside the editor.
Pro Free during beta
Pro Shows table of contents for the document
It supports an outline for the document, by showing a table of contents on the left side of the screen.
Pro Cross-platform
Currently works on Windows, Mac and Linux.
Pro Natural typing experience
Editing in Markdown, either in WYSIWYG mode or in markdown code mode, feels natural. It never gets in the way.
Pro Make charts and diagrams with Mermaid, FlowChart and Sequence
Use fenced code-blocks to render diagrams using syntax from Mermaid and FlowChart.js.
Pro Sidebar with a list of files
You can open any folder in sidebar and see a list of other markdown files.
Pro Syncs with iCloud
Cons
Con Not very powerful as far as text editing goes
nvALT's strength is its search feature. It has some basic text-editing features such as cut, paste, find-and-replace and so on. But it doesn't have any advanced text manipulation features available in other editors.
Con No mobile (Android/iOS) apps
Con In beta
Typora is still in beta and may be prone to changes or bugs.
Con Unusable image management
Con The immediate rendering of Markdown is hard on the eyes
Having Markdown immediately render causes text to jump into formatted text, which is distracting and hard on the eyes.
Con No portable version (Windows)
You need admin rights on a managed Windows computer to install it. There currently is no portable version available.
