I don't use PyPy because when I'm stuck with performance issues, I go to numpy and if it really doesn't work I go to cython/numba (because it means that 99% of

I don't use PyPy because when I'm stuck with performance issues, I go to numpy and if it really doesn't work I go to cython/numba (because it means that 99% of my python code continue to work the same, only the 1% that gets optimized is different; if I'd go PyPy, I'd have to check my whole code again). I do mostly computational fluid dynamics. (nevertheless, PyPy is impressive :-) )