at catprint we are using reactrb (now ruby-hyperloop) to clean up our mess of ruby + JS + HTML + ERB + HAML etc. So far the results have been excellent with a

at catprint we are using reactrb (now ruby-hyperloop) to clean up our mess of ruby + JS + HTML + ERB + HAML etc. So far the results have been excellent with a reduction from about 70K SLOC to 35K SLOC. Some of the other advantages: A common tool chain, including testing (we are using rspec), people don't align themselves as front-end vs. back-end developers, easier training for new hires. Point taken about choosing the "right tool for the job", however there is nothing in JS that makes it a better tool than ruby. In fact I would argue (but it is opinion) that ruby is a far better tool than JS. So why not use ruby for full stack? If I felt that somehow JS was better than we would have worked towards using Node for a full stack solution. Of course its not just the language, its language + available libraries and tool chain. In that regard Ruby is far superior.