Recs.
Updated
Specs
Pros
Pro Capable editor
Cloud9 uses their own editor called ACE. Besides the basics, it covers most important advanced code editor features such as code folding, converting cases, auto-completion, code analysis and refactoring, regex search and offers easy access to relevant documentation.
It also gives access to the CLI, has support for Vim and Emacs keybindings, includes multiple cursors and zen coding mode that removes all distractions and allows focusing on code.
Pro Full terminal access
Cloud9 gives full terminal access to home directory. In their hosted Linux Ubuntu environment it has sudo powers. No UNIX commands have been blocked - npm, ifconfig, chmod, chown, tar, etc work. All commands can be accessed and any package can be installed.
And if the terminal is used when using Remote SSH feature it connects directly to the server and runs the commands on that server.