As people spend more time with Ruby 1.9, JRuby, and Rubinius, we are seeing a lot more benchmarks. It has been a while since we published any metrics, so I thought now would be a good time to summarize our recent experience on some real projects. We chose to measure some different things, however:

• DPC. Developer Productivity, as judged by the Client. This is the percentage of iterations where the client felt that the developers were more productive in Ruby than they would have been with their second choice "Platform B."
• DPR. Developer Productivity, as judged by Relevance. Like above, but in Relevance's opinion.
• DP5. Is Developer Productivity in the Top 5 list of things we would like to have more of? In other words, a project with a high DPC and DP5 means that the client is happy with Ruby, but would be even more happy if Ruby was, um, Rubyer.
• CS5. Is Code Speed in the Top 5 list of things we would like to have more of?

Here's the numbers. The trends are not subtle.

            DPC      DPR      DP5      CS5
Project A:  100%     100%     100%     0
Project B:  100%     100%     100%     0
Project C:  100%     100%     100%     0
Project D:  100%     100%     100%     0

At this point, even caring about Ruby's language performance would be a premature optimization at the business process level. Ruby's runtime performance is a non-issue for a broad spectrum of applications. In fact, I believe that all of our customers would be even happier with a language that ran 50% slower than Ruby, if it also made the development team a mere 10% more productive.