Yea, JF is getting mature enough for more people to transition.
I've been running it side by side with Plex for about 2 years now, and have a couple of clients (and all of my personal use) on JF, but a few users either cant run JF directly on their hardware (and don’t want to cast every time) or they are older and would struggle to learn a new app without some hands on practice with it.
The newest Plex UI update on some devices is causing some problems so I think I’ll have a few more users moving to JF in the near future.
It's a bit of a ram hog compared to plex but that's not a major issue.