Whereas before the Verisign com net registry used to receive all
updates from its registrars and submit the changes to the 13 root
servers every 12AM and 12PM, they now submit them at least 5
minutes after receipt.
One implication of this is that it can result in "faster propagation"
if you're especially switching DNS. Many threads both here and
other forums verify this.
In fact, on the day it went live, I posted here and asked people to
post their results to see if it's true. And practically all of them did
confirm it's happening.
So if you transfer your domain's DNS to a new pair, your registrar
will submit them to the registry, the registry submits them at least
5 minutes after to the 13 root servers, then the ISPs query them
and update their cache.
Of course, it still depends on how soon your registrar submits the
change/s and how soon your ISP updates as well. But at least the
rapid DNS has helped cut down the waiting time.