Having come to PyCon from the world of Microsoft conferences, I was initially shocked that, as a speaker, I had to pay my way. In the old world, I had my travel/hotel paid for; my registration comped; and sometimes even got a speaker gift to boot! It was an abrupt change to speak at PyCon and only receive a little stamp or ribbon on my badge.
Now as much as I like getting stuff paid for, I have to say that I much prefer the PyCon approach: it makes for a much more interesting experience, and a much richer community. It's hard to explain precisely, but I think it has to do with an overall sense of contributing to rather than taking from the community that makes the egalitarian approach to paying for PyCon. In other words, if you aren't willing to contribute the time needed to prepare a session, maybe PyCon isn't the event for you.