Hi Russell,
Unfortunately pip cannot install binaries, so any user that tried to
install matplotlib using pip would have to have a C compiler.
Unfortunately many users do not have a compiler on MacOS and Windows.
This is true, and an important advantage of the binary installer [1].
However, I would venture that most scientific users will have installed a compiler (at least on the Mac) - even accidentally, due to all the complicated installation procedures for many scientific software packages 
In addition, matplotlib has some important dependencies that may not be
available on all systems. MacOS now includes all necessary libraries. I
don’t think that is true for most flavors linux (though there is
probably an easy way to get all missing packages). I have no idea about
Windows.
(Does it even work with matplotlib? I’ve never tried it.)
Pip works beautifully on the Mac since Lion, once you install pkg-config. This allows matplotlib to pick up the dependencies from the system (i.e. libpng, libfreetype and zlib). My shortest suggested route to Matplotlib on Lion is (assuming you have Homebrew installed):
brew install pkg-config
sudo pip install matplotlib
The problem with pip / easy_install is that a lot of people assume that this is the standard way to install Python packages. I don’t blame them - in fact, I would want all packages to be compatible with pip. It’s not the greatest tool, given the pretty sorry state of Python packaging, but it is pretty much the simplest option from the command line.
Best regards,
Ludwig
[1] For me the only downside of the installer is the use of Python.org Python instead of the default “system” Python, as the latter makes more sense to me for a standard installation (and avoids having multiple Pythons on your system, which is a Good Thing). Python.org Python used to be a mandatory install on older Mac systems such as Tiger / 10.3, but this is no longer a compelling argument for me on newer systems.
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On Friday 16 November 2012 at 2:25 PM, Russell Owen wrote: