I've used Numba to speed up some tight numerical computations written on NumPy arrays and it's incredibly good - about as fast as rewriting it from scratch in C

I've used Numba to speed up some tight numerical computations written on NumPy arrays and it's incredibly good - about as fast as rewriting it from scratch in Cython, but much, much faster. The flipside is that it only really results in a speed up for pure numerical code - if you have to use any Python objects, then you lose everything.