The problem with those assumptions are just that, they are assumptions.
Manjaro is fairly stable compared to arch because it clones the Arch repos into it's own, and puts them in different branches. (Arch's Stable = Manjaro's Testing?) Unless Korora does something similar, which it does not, it is the same as Fedora's release cycle - making it immediately prone to the same issues.
As for the "LTS vs Rolling" - It's closer to Ubuntu's non-LTS release cycle, and certainly not rolling (aka: bleeding edge ; Fedora Rawhide):
The Fedora Project releases a new version of Fedora approximately every 6 months and provides updated packages (maintenance) to these releases for approximately 13 months. This allows users to "skip a release" while still being able to always have a system that is still receiving updates.
And yeah... If they ship Proprietary software, their distribution is not "100%" free (Libre OR Gratis) - they are shipping binary packages and unlicensed codecs. This not only may violate the license they release under, but also specific state and international laws on copyright and licensing. (There is a legitimate reason Fedora does not include such things, and it's on both a legal and financial ground)Why Ubuntu doesn't come with support for Mp3s, Flash, and other Multimedia Formats -HowToGeek