Earlier quoted context omitted.
The article you link lists numerous advantages to using Atom over RSS (and no advantages to RSS). Why would you consider RSS over Atom?
That article also has an XHTML 1.0 Transitional DOCTYPE, and wastes a request trying to load JavasScript for Google Plus.... this is not up-to-date information. The "advantages" are minor at best, and exclusively relevant to a developer, with very little impact on the end-user
I have one or two things in my feeds that can’t be expressed in RSS, such as HTML markup in my titles (which I use for , and I think ). I also have angle brackets in a title, which I would be afraid to do in RSS because I’m confident that some clients would butcher it, and they wouldn’t even be wrong since RSS don’t care.