I tried. My company has a python API that we run on our machines, we sell the machines to businesses and don't manage them ourselves. We wanted to see if we could get some easy performance increases without too much investment.

At the time (a year ago) there wasn't a way to precompile using pypy, which meant shipping pypy along with gcc and a bunch of development headers for JIT-ing. Additionally a one of the extensions we used for request validation wasn't supported so we'd be forced to rewrite it. I also found that the warmup time was too much for my liking, it was several times longer than CPython's and it became a nuisance for development. I guess I could've pre-warmed it up automatically, but at that point I had better things to worry about and abandoned trying to switch.

I'm sure, given enough resources, it would be a lot better. But it's not quite as simple as switching over and realizing the performance increases without some initial investment.