One part GvR didn't talk about which is top-notch in PyCharm is jumping around in your source code. The searching of symbols and classes (via a search box) is very well done and generally works quite well, which is extremely handy for big codebases, and the contextual jumps (option-click on a class name) to definitions is quite cool as well.
And in usual Jetbrains fashion, it comes with a bunch of refactoring though they tend to show their Java origin (extract method can handle multiple return values, but provides no way to set the order of the return tuple whereas you can reorder parameters)
Oh forgot one: PyCharm has a very good support for virtualenvs.
It's not quite perfect yet, but you can set a virtualenv interpreter as a project's current interpreter (PyCharm does not automatically recognize that, and that's the major feature lacking) and PyCharm will see the right PYTHONPATH. Very, very handy with `virtualenv --no-site-package` which I tend to use a lot.
And in usual Jetbrains fashion, it comes with a bunch of refactoring though they tend to show their Java origin (extract method can handle multiple return values, but provides no way to set the order of the return tuple whereas you can reorder parameters)