When comparing nvALT vs MWeb, the Slant community recommends nvALT for most people. In the question“What are the best Markdown editors for OS X?” nvALT is ranked 10th while MWeb is ranked 18th. The most important reason people chose nvALT is:
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.
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 Excellent support of LaTeX equations
Math-heavy note takers, look no further. Mweb even supports the basic LaTeX equation labeling and referencing, which you cannot find in any other markdown editor as of early 2018. Library management is another major plus.
Pro Supports publishing to popular web platforms
MWeb can publish Markdown files to various web platforms including (but not limited to) Wordpress, Metaweblog, Evernote, Blogger and Tumblr.
Pro Syntax highlighting in fenced code blocks
MWeb has syntax highlighting for some popular programming languages inside fenced code blocks.
Pro Comes with an iOS app with iCloud sync
Once you are done editing your note on your mac, it's immediately available in your iOS devices, great for checkup anytime as you go.
Pro Drag & drop or paste photos to the editor and display
Supports adding pictures to a Markdown file either through drag-and-drop or by pasting it.
Pro Small but powerful
It has file tree, can post article, can upload pictures, can render in pretty preview themes, and is small and fast.
Pro Supports both its own database and external folders
So you can have a side project stored on its database, and your current notes on external folder, with simple files, that could be share with other apps.
Pro There's a free version, Mweb lite, on Mac OS and iOS
Pro Supports publishing a static blog on FTP
Possible to manage your self-hosted static blog with your own css
.
Pro Tables
Quick insert and editing of tables.
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 Indie app, possible to be abandoned at anytime
If you like the app, please buy it to make it sustainable.
Con Price become expensive
MWeb used to cost $14.99, and could be bought half the price with promo; but version 3 now costs $20, and the developer would like to go to a subscription plan.
Con No free version
MWeb costs $20.99 and is available on the Mac App Store. There's a free trial available but it's only for 14 days which may not be enough to make a good evaluation of the software before buying.
