This year for the first time, PyCon is working with professional meeting planners. Working with Conference Technology Enhancements (CTE) has helped a lot, and I wouldn't want to go back to the old way. Without CTE's help, either PyCon would not have been able to take place in anything near its present form, or I would have lost my job and gone insane. Possibly all of the above.
CTE handled the negotiations with the venue: room rates, catering, A/V, and more. Volunteers did this in the past (Jeff Rush in Dallas, Steve Holden in DC), and perhaps they enjoyed it (although I doubt it), but I wanted to have as little to do with negotiation as possible. Also, CTE continues to offer us a wealth of experience and ideas. For example, CTE originated the idea of significantly increasing the sponsorship levels while increasing our investment (in the Expo Hall, etc.), in order to properly value the conference. I couldn't imagine a conference of this size and complexity without the kind of help CTE brings.
There were some communication issues. While the PyCon organizers communicate by email, IM, and IRC, I had to get used to calling CTE on the phone in order to get a quick response. It was just a matter of getting used to each other's way of working.
We're learning, and I fully expect that this year's experience will improve our working relationship. I would not hesitate to continue our relationship with CTE.