Atom is developed with the community on Github.

Atom is completely free to use.

One of the goals of Atom is to be a text editor for both experienced and beginner programmers. You can add keyboard shortcuts, change themes, install plugins, and change core settings by clicking through a GUI, or by manually editing config files the old fashioned way. It has the added advantage of being built using the same engine that powers Google Chrome, so actions like opening and closing tabs feel familiar even to new or non-programmers.

Runs on Mac, Windows, and Linux.

You can theme and customize Atom to your liking.

Multiple cursors and column selection allow versatile ways of editing.

ctrl + d will select the current word and each time the command is repeated, add the next occurrence of the word to the selection.

ctrl + click or middle-mouse click will place another cursor in the place that's clicked. Cursors can then be controlled together. This also allows selecting vertically.

It's built on web technologies (JS, HTML, and CSS), so hacking for JS devs feels natural.

You don't have to restart Atom after you install a new plugin in order to activate it. It automatically starts working.

Will highlight folders, files, and lines that have any uncommitted edits made. It also integrates really well with GitHub.

Various plugins needed to be installed, but you have feature granularity, such as markdown previews, PDF generation, and even editor styling.

Ctrl or Command + T and using fuzzy search you can look for a file in your project.

Due to its modular design, almost any aspect of the editor can be changed. Even seemingly core packages, like those taking care of search and replace functionality, can be forked on GitHub, and changed and replaced in the editor.
The documentation for creating new plugins is also great, making it easier for developers to jump in and create plugins for Atom.

Atom has a built-in package manager and an extensive list of packages. Packages are written in CoffeeScript.

Atom qualifies to be a good IDE because of the packages like linters, atom browser and hydrogen.

The Command Palette permits fuzzy searching all available functions, settings, snippets, etc.

Atom was built from the ground up with the community in mind. Package management is therefore a first class feature.

Installing Atom adds two command line commands - atom and apm. The first one runs the application itself and the second one is the Atom Package Manager that's used to add and remove various components from the package listing. While these features can be set up with other editors as well, Atom takes care of them out of the box.

Arduino is the most important platform for developing embedded systems.

The editor is built on top of Node. As such anything that can be done in Node can be done in the editor.