Chris Wellons, developer of Elfeed, an Emacs newsreader, writes on his blog:

At this point I’m quite confident in saying that Atom is by far the better specification and I really wish RSS didn’t exist.

When creating feeds, RSS 2.0 is often the default, but switching can be easy. For example, in Django, to provide an existing newsfeed (MyFeed) as Atom v1.0, you simply set the appropriate feed_type attribute:

from django.utils.feedgenerator import Atom1Feed

class MyFeed(Feed):
    feed_type = Atom1Feed