Primal has a decent moat because of the web version, so it’s easier to slap it onto webapps that use nostr. 

I currently use nostter to show people their profile and because I think the design is adorable, but I let them connect/view global feed on primal.net

Damus as an app is way more reliable and performant. No problems uploading content like videos or images, speed is super consistent. Seems like more focused engineering on Damus.