Same. I'm still primarily a Plex user for the player (it's just easier for sharing libraries with everyone) but I love the arr stuff. Just got readarr setup for audio books and audiobookshelf for the player which is really nice.
Probably my favorite feature of the arr suite is in Radarr and list subscribing. I've got mine connected to some good letterboxd lists along with things like tmdb popular to keep my library up to date with recent stuff. Also there's some podcasts I listen to like The Rewatchables. I just subscribe to the lists of movies on letterboxd and I can easily keep up with the podcast.
I've been very happy with a couple of indexers that I have paid for. I haven't needed to really jump into the invite only world. There really is A LOT of content available easily. I'm sure more niche content might need more select access, but for me I haven't gotten there. There was one Charlie Brown I have on VHS that took forever to find a better copy of, but I did eventually get a better version.