It's not ready for end-user yet, I agree on that part. However I experimented with CoreCLR on Linux and managed to get things running. It will most likely take another 6 months or so to polish all those and we'll get ourselves a new cross-platform language.

So it is on windows too (As the software is in its beta phase) .

RyuJIT is included with .Net 4.6, which RTM'd last week. It's production quality on Windows. It's probably an older and more stable version of what is on GitHub.

You are correct. Ryujit is ready for production but coreclr has other parts that are different from .net 4.6 and coreclr specefic (like PAL for non windows) which is not production tested yet.

I am using Mono on Linux as a backend service and it works pretty well.

Mono has worked fine for me in the past but I was more referring to CoreCLR which is consistently called 'cross-platform' now but is far from it as their own tooling crashes all over the place when attempting to use it (dnu restore, dnu install, dnx . run, etc).

Yeah I know, was just saying there was a viable platform for back-end C# development.

I hope both teams do not duplicate work and are happy to share design and code changes. C#/.NET is nic, I think it still has potential to compete for Linux server back-end services with Go and Java.