Anyone got any good examples major program written using Numba? Plenty exist for Cython -- I run into those all the time.

Not sure if a major program but here is a recent and promising one: https://github.com/lmcinnes/umap

fastparquet https://github.com/dask/fastparquet

Do you mean top-to-bottom Numba-jitted? Or projects/libraries that use Numba to speed up parts of the code?

Datashader (http://datashader.org)