.NET CLR faster than JVM for dynamic languages

An interesting post from the dude that originally ported Python to the JVM and who just finished version 1.0 of the .NET Python port:

I started work on IronPython almost 3 years ago. My initial motivation for the project was to understand all of the reports that I read on the web claiming that the Common Language Runtime (CLR) was a terrible platform for Python and other dynamic languages. I was surprised to read these reports because I knew that the JVM was an acceptable platform for these languages. About 9 years ago I'd built an implementation of Python that ran on the JVM originally called JPython and later shortened to Jython. This implementation ran a little slower than the native C-based implementation of Python (CPython), but it was easily fast enough and stable enough for production use - testified to by the large number of Java projects that incorporate Jython today.

I wanted to understand how Microsoft could have screwed up so badly that the CLR was a worse platform for dynamic languages than the JVM. My plan was to take a couple of weeks to build a prototype implementation of Python on the CLR and then to use that work to write a short pithy article called, "Why the CLR is a terrible platform for dynamic languages". My plans quickly changed as I worked on the prototype, because I found that Python could run extremely well on the CLR - in many cases noticeably faster than the C-based implementation. For the standard pystone benchmark, IronPython on the CLR was about 1.7x faster than the C-based implementation...