When comparing typora vs Gitbook, the Slant community recommends typora for most people. In the question“What are the best (free) GUI editors for writing structured documentation, e.g. for pdf or html output?” typora is ranked 2nd while Gitbook is ranked 3rd. 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 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
Pro Ability to accept donations for books
If donations are set up, users have the ability to choose if and how much they want to spend on a book. It's limited to $100 per donation.
Pro (planned) Ability to automatically distribute books to online retailers
Gitbook plans to soon release a feature that allows easily distributing your books to Amazon, Apple's App Store, Google Play, Kobo Store.
Pro Includes good analytics
Pro All authors keep rights to their books
Pro Includes promotion tools
Pro Versioning with Git
Version control is based on GIT scm.
Pro Free support for custom domain names
Cons
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.
Con Web-based editor is awful
Slow, unpredictable, slow, painful UI, also, slow.
Con Wire transfers are US only
Ability to automatically deposit revenue in your bank account is limited to United States. PayPal deposits work internationally.
Con Donations are buggy
The form for donations automatically changes to a credit card information form as soon as any amount of money is entered in the form field for donation amount. In addition to the process being jarring, it also does not allow you to finish entering the amount and there's no way to change the amount after the form has changed. Also, the site says they limit donations to $100 USD, but higher amounts can be entered with no indication that they wouldn't go through.
