PyPy’s developers have whittled away at this issue and made PyPy more compatible with the majority of Python packages that depend on C extensions. NumPy, for instance, works very well with PyPy now.

Both fast and easy Aside from speed, PyPy’s big appeal is its ease of use. Unlike Cython or Numba, which require rewrites of Python apps, PyPy is a drop-in replacement for CPython.

"The dual update of Python 2.5 with Stackless 3.1 gives a major boost in efficiency by allowing frequent operations to be executed 10 times faster than the previous versions." ...