I've never used Rubinius in production but over 10 years ago, when I was still relatively new to Ruby, I used to read Rubinius source code to understand how some Ruby methods worked under the hood.
Even though Rubinius has never reached the popularity it aimed for, I'm forever grateful for the effort that's been put into creating it.
Hi, Evan Phoenix, Rubinius creator here. I just wanted to stop in and say thank you for this comment. It means a lot to me, even after all these years that Rubinius helped you out.
Hi Evan, I'm happy you found this comment heartwarming. Your work on Rubinius (and even more - Puma!) was really amazing, it had a big influence on my career
It was incredibly useful for that, except for the occasions where Rubinius got things wrong. :-)
It was also fascinating seeing how the abilities of their VM fed into the design of the core library. I remember soon after starting work on TruffleRuby starting to look into the performance of some string methods and doing extensive refactoring because the type of code that performed best for us was very different.
Even though Rubinius has never reached the popularity it aimed for, I'm forever grateful for the effort that's been put into creating it.