When comparing Eclipse Che vs JSFiddle, the Slant community recommends JSFiddle for most people. In the question“What are the best cloud IDEs?” JSFiddle is ranked 5th while Eclipse Che is ranked 6th. The most important reason people chose JSFiddle is:
In addition to supporting JavaScript and CSS, language settings can be switched to CoffeeScript and SCSS.
Specs
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Pros

Pro Docker runtimes
You can choose from pre-configured environments for Java, Javascript, C++, PHP, C#, etc., or you can define your own by dropping in a Dockerfile - makes it easy for simple and complex projects.

Pro SSH + terminal
Built-in terminal with root access so you can make changes to your running machines. Being able to SSH into the workspace so you can use a desktop IDE is handy.
Pro GIT and SVN VCS support
Projects can be easily imported from any Git or Svn repository hosting service.
Pro Reproducible environment

Pro Custom commands
You can package up custom commands with your workspace and then use them (or share them) with everyone else.

Pro Portable workspaces
The workspace in Che includes project sources, IDE and the runtime. So if you hand your Che workspace definition to another user and they execute it they will get everything they need to build, run and debug the project.
Also the runtime is in a Docker container so it will work even if the second user is on a different OS than the original user who shared their workspace with them.

Pro Previews
Che does a nice job to automatically map the service:port running in the Docker container (e.g. tomcat on 8080) to the Docker port it actually uses (something in the ephemeral range). You never need to figure that out - it's just made available when you run your server.
Pro Merge tool for VCS

Pro Open-source
Pro CoffeeScript and SCSS support
In addition to supporting JavaScript and CSS, language settings can be switched to CoffeeScript and SCSS.
Pro Allows collaborating on code
JSFiddle makes it easy to save the code snippets and send the link to others who can view and edit the code.
Pro Supports a wide variety of frameworks and extensions
JSFiddle can switch to selection of frameworks and extensions including jQuery, AngularJS, ReactiveJS, D3 simply from a dropdown.
Cons
Con Slow runtime
Online IDE is much slower than desktop one.
Con Not actually an IDE
JSFiddle is not actually an IDE and is only suitable for small blocks of code.