The major thing holding them back among my friends and family is the lack of a proper iOS app. I know they have one on testflight, but it's been there for literal years and I haven't seen any progress being made to a full release.

I love audiobookshelf! Been using it for close to a year now, and my only real complaint is the android app doesn't handle podcasts the best (doesn't auto-advance so it makes it a bit annoying to use shorter podcasts), but audiobooks are very easy to access. I have mine set up for remote access, so I can listen to either wherever I am (or just download what I want if I don't have data)