Dare Obasanjo sez "...Based on my experiences working with syndication software as a hobbyist developer for the past year is that the ATOM syndication format does not offer much (if anything) over RSS 2.0 but that the ATOM API looks to be a significant step forward compared to previous attempts at weblog editting/management APIs...."
I've come to a similar conclusion about RSS 2.0 vs. ATOM syndication but am still not sure about APIs.