I recognize editor preferences is a deeply personal taste but it's been very different for me. :) I used to swear by IntelliJ but after taking a day to configure Sublime Text (and then vim), I very much prefer them.

Pycharm has automatic formatting, much better autocompletion (it deduces type based on context), continuous PEP8 check, class hierarchy, refactoring support and a terrific debugger.

Don't get me wrong. I am not trying to bash your choice. I am merely curious how to achieve the similar in vim, because I have some urges to switch as well.

Mostly through plugins really.

Jedi is really awesome for autocomplete: https://github.com/davidhalter/jedi-vim

This plugin really helps in formatting code: https://github.com/hynek/vim-python-pep8-indent

There's another plugin that helps with PEP8 linting: https://github.com/nvie/vim-flake8

I just use a combination of print statements and pdb for debugging, I don't trust automatic re-factoring for Python though, so I tend to do them manually with regex.

What really helps vim beat PyCharm/IntelliJ for me is the fact that I work with a lot of C code as well as Python. IntelliJ's C support sadly isn't quite there yet.