I only scanned the article very briefly, but my impression is that the important comparison is vs. Matlab. The other players aren't really in the author's game. It's a question of the use case and the community and the library support.
In theory, .Net could displace Matlab or Python as the canonical platform for scientific researchers. And in theory Python could displace PHP as the canonical platform for classic CRUD web apps. In practice neither is likely to happen, no matter how much we might or might not wish it to.
I've been a Matlab user for 10 yrs, recently switched to python because of the increased flexibility. never going back to Matlab ever again. Python math and science libs can be a little rough around the edges, but the flexibility more than makes up for it for me.
I'm a Matlab user myself, but I try to use Ruby whenever possible if for nothing else but to just get away from all the god damned matrices. I didn't realize Python had similar capabilities, I look forward to trying it out. But does Python have "Index exceeds matrix dimensions." errors? I just can't imagine life without seeing a few of those every day. That said, the workspace is really handy, is there some equivalent GUI in Python?
Check out EPD: http://www.enthought.com/products/, particularly the ETS framework. It contains almost all the popular scientific/numeric libraries in python and is free for academic use (and much of it is open-source).
As infinite8s points out, EPD from enthought is really quite nice.
Personally, I rather like Python XY ( http://www.pythonxy.com/ )though. It is totally free, open source, and for small little scripts I am a huge fan of the Spyder IDE. It lacks some of the features of bulkier IDEs so I also use Eclipse from time to time. But Spyder is light and much faster than Eclipse with every feature I would want when working on small projects that can be contained in just one or two files.
In theory, .Net could displace Matlab or Python as the canonical platform for scientific researchers. And in theory Python could displace PHP as the canonical platform for classic CRUD web apps. In practice neither is likely to happen, no matter how much we might or might not wish it to.