The application was originally created by Adobe, but is now maintained by the community.
Brackets comes with some very interesting features, like a quick edit mode (Ctrl +e) that brings the relevant CSS for the selected tag in the main editor or live browser previews - the changes are pushed instantly to the browser (Chrome only), without having to save the changes or reload the page (see video below).
Furthermore, Brackets supports extensions for adding extra functionality - more than 100 extensions (as of november 2013) can easily be installed through the built-in Extension Manager:
Brackets for Linux was released back in August and while the Linux builds are practically at feature parity with the the Mac and Windows builds, there are some known issues. For instance, Brackets doesn't currently use native OS menus so under Unity, the menu isn't displayed on the top panel. There's also an issue that occurs when closing the application: you must click the close button twice to get the application to quit. More info about the Linux version, HERE.
Below you'll find an introduction video for Brackets (the video is old, but it should be enough to get an idea on what Brackets can do and why it's different from other code editors):
https://www.youtube.com/watch?v=rvo3Mv1Z4qU (direct video link).
Even though there are deb packages available for download on its website, users must manually download and install each update, and Brackets is updated quite often, usually every 2½ weeks. For this reason, WebUpd8Team have created a Brackets Ubuntu PPA which makes it easily to stay up to date with the latest Brackets Linux builds in Ubuntu and derivatives.
Install Brackets in Ubuntu via PPA
To add the Brackets PPA and install the application in Ubuntu (and derivatives), use the following commands:
sudo add-apt-repository ppa:webupd8team/brackets
sudo apt-get update
sudo apt-get install brackets
Source : WebUpd8.org