Recs.
Updated
Specs
Pros
Pro Gives users access to a terminal with root 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. However, certain advanced features are inaccessible (one cannot run Docker within the terminal).
And if the terminal is used when using Remote SSH feature it connects directly to the server and runs the commands on that server.
Pro Can be hosted on your own server for added security
Since Cloud9 is an open source project with source code available on GitHub, it can be run as a self-hosted solution on own hardware and behind a firewall as long as it's being used on non-commercial projects.
Pro Has a great 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 Debugging with breakpoints for NodeJS server side JavaScript
Breakpoints allow specifying a stopping points in the execution of the application. When these breakpoints are hit, the application will stop executing and give the ability to examine data such as local variables, run commands and control the execution flow of the application.
Pro Lets developers connect to their workspace directly using SSH
Allows you to connect directly to your external server via SSH. Modifying files directly on your server using a cloud based editor allows you to have the portability of the a cloud based workspace with the control of your own server (including complete DNS control).
Pro Very easy to install packages through the built-in package manager
Similar to package managers for the desktop, Cloud9 also includes their own package manager, c9pm, which allows adding new software from a list of available utilities.
Apt-get can be used in the project's workspace terminal to install/update/upgrade software. Composer, Bower or any other utilities of choice can be installed to manage dependencies and packages.
Pro Very easy to deploy apps from inside the IDE
Cloud9 allows quickly deploying apps via CLI. There are instructions on how to deploy to Azure, CloudFoundry, OpenShift, NodeJitsu, Modulus and Heroku. For example, all hosted environments have Heroku's toolbelt installed by default so all heroku commands are available from the get-go.
Cons
Con You need a credit card to sign up
You need a credit card to sign up for Cloud9, which is problematic for users in countries where credit cards are not the norm.
They won't bill you (for the free account), but still require it. You can buy a VISA gift card and sign up with that.
Con Runs on Amazon Web Services
I used Cloud9 several years ago and it was great. Today I went to sign up with a new user for a new project. I was redirected to AWS . I jumped through hoops for a couple of hours and just couldn't get it working so eventually gave up. Fortunately my old user still works at c9.io but I really don't know why Amazon has to make it so complicated.
Recommendations
Comments
Flagged Pros + Cons
Con Non free/libre
The source code is published under a non commercial which makes this software non libre/open source. See the definition of the FSF and the OSI.
Out of Date Pros + Cons
Con Requires Credit Card to register
You are directly asked for a Credit Card while registering.
Con Lacks subdomain options
Building an app that needs subdomains is impossible.