[CentOS] postfix as default MTA

I noticed when CentOS 6 came out that RHEL had moved to postfix
vice sendmail as the default MTA. I had never heard the rationale
given, it always sat on the back burner, but I was reminded of the
question the other day when I was dealing with a related topic.

I don't want to get into a pissing contest about how one MTA is
obviously better than the other, nor why others think that I should
prefer one over the other, but I *would* like to know what
rational (if any) RedHat gave on the move.  My google-fu hasn't
been successful in finding it and I didn't see anything in the
CentOS archives on the topic.

Does anyone remember the reasoning, if given?  In particular, I'm
wondering if it was due to integration with any other specific 
subsystem or software product.

Devin