When comparing Eclipse Che vs Xamarin.Android, the Slant community recommends Xamarin.Android for most people. In the question“What are the best IDEs for Android development?” Xamarin.Android is ranked 5th while Eclipse Che is ranked 11th. The most important reason people chose Xamarin.Android is:
Xamarin is a platform on which you can build cross-platform mobile applications for Android, iOS and Windows Mobile and use only one codebase.
Specs
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Pros

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

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 GIT and SVN VCS support
Projects can be easily imported from any Git or Svn repository hosting service.
Pro Reproducible environment

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 Cross-platform
Xamarin is a platform on which you can build cross-platform mobile applications for Android, iOS and Windows Mobile and use only one codebase.
Pro Fast build
Faster compared to Gradle-based systems.
Pro Allows .NET programmers to write Android Apps
Allows .NET programmers to write Android Apps.
Pro Programming in C#
Allows you to write your programs in C#, a language much superior to Java, regarding expressiveness, readability and overall productivity.
Pro Open source
Xamarin.Android and the whole Xamarin SDK is free and open source and released under the MIT license.
Cons
Con Slow runtime
Online IDE is much slower than desktop one.
Con Lacking third-party library support
Having to use third-party libraries in Xamarin can be a real pain. Since Xamarin uses C# and third-party libraries are written in Java, you have to create bindings to use them in a Xamarin app. Which is cumbersome and wastes a lot of time. Especially considering that the Xamarin docs are not very good when it comes to this part.
Con Too large to download
Since core Visual Studio comes about in 543 MB of download size, the Mobile App Development with C++ workload comes about ~4 GB, the issues with your bandwidth and internet connection can cause the components to re-download, wasting a considerable amount of internet.
