What annoys me is the name. Early morning it took me a moment to realise that PyPy is not PyPi, so at first I thought they referred to PyPi. Really, just for the name confusion alone, one of those two should have to go.

Edit: I understand the underlying issue and the PyPy developer's opinion. I don't disagree on that part; I only refer to the name similarity as a problem.

Wikipedia tells me that the package index PyPI (launched in 2003) is about 4 years older than the interpreter PyPy (first released in 2007).

Still, at its core, PyPy is a Python interpreter which is itself written in Python and the name PyPy fittingly describes its technical design.