No, copr[1] is to Fedora as the AUR is to Arch, and as PPAs are to Ubuntu.

RPMFusion a very longstanding and trustworthy repository for software that fedora/RedHat can't/won't distribute. Many of the RPMFusion maintainers are also maintainers for fedora packages in the official repositories. RPMFusion is of very high quality and doesn't often break . You don't really have to worry about some Joe Shmoe putting together a rpm spec that backdoors your machine, just add the RPMfusion repository and you can forget about it.

That type of attitude should not apply to things like PPAs, the AUR, and copr. Anyone can put anything up and you're trusting random people online to not bork your machine. With RPMFusion you're still trusting internet strangers, but they have a solid track record of many years and it's effectively no different from trusting the maintainers of official packages.

[1]: https://copr.fedorainfracloud.org/

In the past, I might have said that there were some major similarities, but not so much now. The issue that I see with AUR is that each one is really independent and there isn't much of an assurance as to how well updated it would be. In the past, RPMFusion was also too slow to update for me, though, and I would frequently deal with update failures because of it.

But that changed a few releases back. I literally just updated from Fedora 26->27 and all of the RPMFusion packages were automatically upgraded along with it. I have also found that the repo maintainenance is exceptional at this point.

I think that the Fedora equivalent of AUR is probably COPR, but COPR probably isn't as good as AUR overall.