When comparing Emacs vs Notepad++, the Slant community recommends Emacs for most people. In the question“What are the best programming text editors?” Emacs is ranked 9th while Notepad++ is ranked 13th. The most important reason people chose Emacs is:
Emacs can be controlled entirely with the keyboard. While true, I often find the mouse and menus handy for those lesser-used commands. An aide-memoir.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Keyboard-focused, mouse-free editing
Emacs can be controlled entirely with the keyboard. While true, I often find the mouse and menus handy for those lesser-used commands. An aide-memoir.
Pro Total customizability
Customizations can be made to a wide range of Emacs' functions through a Lisp dialect (Emacs Lisp). A robust list of existing Lisp extensions include the practical (git integration, syntax highlighting, etc) to the utilitarian (calculators, calendars) to the sublime (chess, Eliza).
Pro It's also an IDE
You can debug, compile, manage files, integrate with version control systems, etc. All through the various plugins that can be installed.
Pro Free
Licensed under GNU GPL.
Pro Self documenting
Emacs has extensive help support built-in as well as a tutorial accessed with C-h t.
Pro Works in terminal or as a GUI application
You can use Emacs' command line interface or graphical user interface.
Pro Great documentation
With 30+ years of use the Emacs documentation is very thorough. There are also a lot of tutorials and guides written by third parties.
Pro Ubiquity
Fully compliant GNU-emacs is available on many platforms, and they all understand .emacs configuration files.
Pro Lisp customizations
With lisp customization, any behavior of Emacs can be changed. Update with pre-release patch can be also applied without recompiling the whole Emacs.
Pro dabbrev-expand (Alt-/)
Dynamic word completion.
Pro Provides org-mode
Advanced planning and publication which can start as a simple list.
Pro Mini buffer
You can pass complicated arguments in the mini buffer.
Pro Enormous range of functionalities (way beyond simple "text editing")
Through its programmability, a very broad range of functionalities can be integrated in emacs, turning it even into a "single point of contact" with the underlying operating system.
Pro Rectangular cut and paste
Emacs can select rectangularly.

Pro Vi keybindings through Evil mode
Evil mode emulates vim behaviors within Emacs. It enables Vi users to move inside the Emacs universe.
Pro Has been widely used for a long time
The first verion of Emacs was written in 1974 and GNU Emacs in 1984.
Pro Visual selection and text objects with Evil
Evil is an extensible vi layer for Emacs. It provides Vim features like Visual selection and text objects.
Pro Support multi-line editing, multiple frame, powerful paren, crazy jumping style
Review the "Emacs Rocks" video.
Pro Cross-platform
Works on Linux, Windows, Macintosh, BSD, and others.
Pro Integrates planning in your development process
You can jump straight from your org-mode files to programming tasks - and back - and build a seamless workflow.
Pro Helm plugin adds even more power to Emacs
Powerful commands, search, and more with the Helm plugin.
Pro Versatile
Emacs is great for everything.
Pro GTK+ widgets support
Since version 25 you can run GTK widgets inside Emacs buffers. One of these is the WebKitGTK+, which allows the user to run a full-featured web browser inside Emacs with JavaScript and CSS support among other things.
Pro Excelent tutorial to get you started
The tutorial you are presented with at startup shows you exactly what you need to get started and teaches you how to use the built-in help yourself later.
Pro Interactive Shells
Emacs has a number of shell variants: ansi-term, shell, and eshell.
Pro Gnus
Managing several large mailing lists has never been easier using Gnus. The threading commands and the various ways of scoring articles means that I never miss important messages/authors, etc. A joy to use.
Pro eshell is cross platform
You can use the underlying operating system shell as a terminal emulation in an Emacs buffer. Don't like the default shell for your configuration? You can change it to your liking.
Pro Excellent Lisp editing support
Built-in packages make editing Lisp source code feel natural.
Pro use-package and org-mode
Missing some neural package that predicts actions
Maybe in the next release ...
Pro Syntax highlighting for a wide variety of languages
Notepad++ has built-in support for syntax highlighting for a wide selection of programming languages.
Pro Light and fast
Notepad++ is a very light program that starts almost instantly. This makes it a great text editor for users that want something that will start the second they open it.
Pro Portable
You can get a portable version of N++ and put it on a flash drive or your dropbox account and have your editor, configured the way you like, at any computer that you are on.
Pro Extendable via plugins
A list of hundreds of plugins is maintained.
Pro Free under GPL
Notepad++ is licensed under GPL, which means it is free/open source software that you can use freely.
Pro Regex replace in selection, active tab, or all tabs
In Notepad++, the user can utilise regular expressions to quickly modify text across multiple files.
Pro Persistent documents, even after exiting the application
If you close Notepad++ (npp), your documents remain even if you haven't saved.
Pro Split screen
The user can open and edit files in multiple screens within the editor window.

Pro Multi-line editing
While it is disabled by default, when enabled, it is possible to edit more than one line at a time. This is helpful in many situations.
Pro Easy to use and admin
Very easy to use and personalize.
Pro User defined language syntax support
You can define your own custom syntax highlighting rules (or add support for others) .
Pro Supports Markdown
If you have the Plugin Manager installed you can search for MarkdownViewer++ and install it via that plugin.
Cons
Con Learning curve is long
While it's better than it used to be, with most functions being possible through the menu, Emacs is still quite a bit different from your standard editor. You'll need to learn new keyboard shortcuts.
Con Sometimes the extensibility can distract you from your actual work
If I ever want to lose half a day, I'll start by tweaking my .spacemacs config file.
Con Keyboard combinations can be confusing for new users
For example, for navigation it uses the b, n, p, l keys. Which for some people may seem strange in the begging. However they can be changed easily.
Con Documentation is not beginner-friendly
Although lots of good built-in documentation _exists_, I have after four years of Emacs as my primary editor not figured out how to actually make use of it, and rely completely on Google / StackOverflow for help.
Con Hard customization
For customization, you need to learn Lisp
Con A lot of jokes in this serious software
Con Using Emacs on a new machine without your .emacs file
Con Windows-only
While it can run in Wine, it is native only to Windows. Linux users will have to use Notepadqq instead.
Con Outdated UI
Only the text area can be themed, and it doesn't have as many features as browser-based text areas.
Con Limited new syntax support for new languages
It may be hard to find good plugins for relatively new languages.
Con Settings confusingly scattered
Examples: try to change the tab size or used font.
Con Session backups not enabled by default
Unsaved tabs will be lost when Npp crashes, unless you first enable the session backup option.
Con User defined language doesn't support triple quote strings
It also doesn't support triple hashed comments. Both styles are overridden by their single character single line version.
Con Annoying update notifications upon start-up
Annoying update notifications tend to pop up upon start-up after not having used the app or machine for a few days. At the same time, they can be easily turned off.
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