I had a few questions about the actual implementation of this stuff. I took the coursera ML course, so much of the terminology and techniques are familiar after that, but Professor Ng structured the exercises in the course around Matlab/Octave and suggested using one of these tools for a first-pass solution when implementing machine learning problems.

Have you used Matlab much in your work? How does the performance (and libraries available) compare with Python?

Also, does anyone know a good resource for finding good, high performance ML libraries for other languages (Ruby, C++, etc.)?