I think Damus is just a much simpler UI and UX. Much more oriented for beginners.

I like to think of Ameythst as the Swiss Army Knife of Nostr Clients. I prefer it for a lot of reasons, but Damus would be much better for beginners that are new to Nostr. I would much rather promote Damus to folks I know to get them started using Nostr.

Primal is simple setup for beginners, but as I said before so many issues. 

 As far as I'm concerned, Primal, being Italian, has only one flaw: no translation service, not even third-party ones.
Otherwise it has improved a lot and the search works better than Amethyst, both for users and topics.