I think one of the most exciting things about PyPy that sometimes get lost is that it's not only a great interpreter, it's a great interpreter construction toolset. I like python the language itself quite a bit, but if I were writing an interpreter for a new language PyPy would probably be the platform I'd want to implement it on.
I was doing a homework for an algorithms class today. I wrote a quick implementation in Python with some quickcheck tests to make sure it worked correctly. Running 10,000 tests with CPython 2.7 took 136s on my laptop. For fun, I tried with the latest PyPy and it ran the 10,000 tests in 30s. This is very impressive and I am definitely going to start using PyPy more often.
I have been recently porting to Python (with NumPy) some badly written C++ code. I was really shocked that the performance drops nearly 100 times (because of many nested loops).<p>NumPy working on PyPy would probably get me really near original performance. And it's not the advanced features I hope for -- ndarray and basic linalg operations is all I need to do my thesis.<p>Anyway guys, great job so far, looking forward to the future.
Why does the official Python development still take part in CPython rather than PyPy? Is there anything seriously wrong with PyPy, so it can't replace CPython by now?