i currently have my feed reader (Net News Wire) to check for new feeds every hour. Seems to work, but like you said, noit for all categories. I checked it tonight, and had 15 new posts. Upon logging in the regular way, I find that there are 8 pages of threads that I have to read. Not sure what, but something is not set right.
As far as the whole logging in thing, I have my Mac set up to auto log in to this and other boards. When I click on a post from an rss feed, it takes me right to the board area where the post was made.