Almost everything is better refined under Fedora. Most recent example: I support a lab that teaches embedded development. The ARM devices present themselves to a host as a USB network device with DHCP. If we attach those devices via USB to an Ubuntu host, it switches the default route to the embedded device, which means the host loses access to the NFS server and the whole desktop session hangs. On Fedora and CentOS, the hosts correctly get an address and a subnet route, but the default route is unmodified, so the system continues working.
Ubuntu and Fedora are mostly the same software, so it's hard to find "big" reasons to choose one over the other. Instead, it's the details that really make Fedora stand out.
The sad thing is that it's always been this way. Ubuntu made a splash in its initial releases, claiming that they'd made Linux "just work". The truth was that Red Hat, GNOME, and other groups had been making all the bits just work for a long time before Ubuntu was released, Canonical merely released a distribution just as those bits were getting finished. Fedora's release at that time was a major jump in usability from the previous release, and "just worked" as well.
Fedora has always been the more refined platform in a long list of ways.