Really?
I used Aptana, which includes the Pydev plugin. I notice everyone seems to give PyCharm lots of love, and have been tempted to try it. Autocomplete is one of the features I rely on heavily.
I used Eclispe/Aptana/PyDev at a previous job and it was pretty nice, but PyCharm is superior in my opinion. In addition to great completion and code navigation, it also gets Vim emulation mostly right. PyCharm is also a mostly out-of-the-box experience, whereas it took a while for me to get Eclipse set up just right.