Ofc, Arch users should learn how to resolve a package conflict, or how to downgrade packages, or generally how to debug the system. Sometimes you also have to migrate config files.
On the other hand, as an arch user, I can tell that it mostly just works. If you customize heavily an ubuntu, it will break more likely. And while you can fix an arch, you probably have to reinstall an ubuntu.
Moreover, Arch has a testing repository which is not the default.