Mac desktop apps tried so far:
Mastonaut - Straightforward UI. Minor bugs on machines with multiple monitors. I like the experience, but can't find search in the UI.
Hyperspace Desktop - Clean UI. I like the Activity and Recommended features. But I want to see my notifications and at least one feed at the same time, and Hyperspace doesn't do that. Might be good for easily distracted people who want to focus on one timeline at a time.