Recs.
Updated
SpecsUpdate
Pros
Pro Extendable
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.
Pro Beginner friendly
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.
Pro Extensive list of packages
Atom has a built-in package manager and an extensive list of packages. Packages are written in CoffeeScript.