I got a handful of peculiar errors on a fresh install, so I decided to create a fresh and clean environment within Anaconda to retest the installation (incidentally, the issue I was running into was a dual definition of QDate format, once set at 1 and once set at 2. Running fatiando.test() resulted in one failure. Had a hodge podge installation so that's why I decided to clean install).

Operating system: Windows 7 Enterprise, SP 1
Anaconda 2: 4.4.0 x86-64
Fresh environment in Anaconda, using 2.7.13.

Installation steps:
1:
conda install fatiando mayavi --channel conda-forge
(ran without error)
2:
python -c "import fatiando; fatiando.test()
(received error that pytest was not installed)
3:
conda install pytest
(installed)
4:
repeated step 2. This time, the test had a different look--it was almost like it was on a verbose setting. It passed with 8 warnings (attached file).
5:
Attempted to run gravmag_mag_prism.py from the cookbook, and got a mayavi error (your favourite). The 2D plot looked fine. Error output attached in second part of the file. At the error's suggestion, I tried:
6:
conda install pyqt
I had it, superseded 27_4 over 27_2
7:
conda install traits
superseded py27_1 over 27_0
8:
conda install mayavi
This was interesting. One would think it would have installed everything it needed in step 1, but it didn't. It installed tk, changed the version of matplotlib, and downgraded pyqt. This resulted in the same error I had which started this whole thing (part 3 of the file).

fatiando_install.txt

No idea at this point. Not a huge priority, but reporting it anyway.