Uhm I think you mean Leap. Slowroll is really new and an amazing concept.
Semi-rolling with a few packports and a short feature delay of 3 months.
Fedora is fine, but they dont have the longterm kernel. You can stay on the older supported version for more stable software.
Fedora KDE broke for me once with very very nontrivially fixable DNF and RPM issues. Pretty insane. Fedora upgrades are messy and weird.
Fedora Atomic though is nearly unbreakable. Though, NixOS might be better as /etc (and with home-manager /home) are manages and dont accumulate garnage and state