Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
I'm not even sure it is right to say "hot on the heels" of Fedora, because the release of Korora 19 came so close behind Fedora 19.
As far as I can tell they were released on the same day, and their release announcements are consecutive on Distro Watch. I see this as a testament of the hard work put in by the Korora developers, and the fact that Fedora 19 had a smooth development cycle and was pretty stable for quite a while before it was released.
Korora is the "everything is in here" derivative of Fedora. One of the things that Fedora gets knocked for is the lack of some popular features and packages (let's not get into a discussion of the why and why not); if anything, Korora has gone to the other extreme, and the base distribution includes lots and lots (and lots) of packages.