I haven't finished the talk yet but PyO3 was the best thing to happen to me. I reimplemented a huge amount of my python code in Rust with it and gained enormous performance benefits, though it was hard to get the async to work well.
I liked pyo3, but it added 10 seconds to the build. Maturin seemed like clutter to me. In the end I replaced all our python code with rust. OK that was only 13kloc.