Canon RF 28-70 f/2 review by Fro

[mirage]

My feeling is Canon deserves a fair bit of credit for managing to make EF lenses perform as well on the R as they would on a (similarly spec'ed) DSLR body, and making the transition to the R mount as painless as possible for EF lens owners.

yes. But it was clear all along to anybody following Canon / developments and drawing the obvious conclusions.
Canon also "had to" ensure max. compatibility of EF lenses, since they could not possibly bring a full RF lens lineup on day 1.

From the bits I've read, it doesn't sound like Nikon has done as well with the Z/F adapter.

Nikon FTZ adapter works just as well for all *current* Nikon F lenses. Limitations only apply to "decades old Nikon shards". I understand that those affected are not really happy, but some things are just technically not possible. Nikon owners were spared the hard transition to an "electrified mount" Canon made in 1987 [FD -> EF], so they have to take some incompatibilities using old lenses on new camera bodies now. No reason for much whimpering really.