I've personally used Feedburner for most of my feeds during my first year of podcasting. I've heard both sides of the story: some advocate using it because it makes it simple to change your feed if you have to move it for some reason; others say no, as in Daniels' case, because it apparently can cause problems. I haven't seen any problems with using it. In Feedburner, I simply duplicate the settings I have set up in PowerPress for the show(s).