I've been using it since the fork from Emby and it works well for what I use it for.
That said, they're right IMO to redirect funds to the clients. The Android TV app is in a really rough state. The regular Android and Web interfaces work great, Roku as far as I recall works well...but the Android TV one is really not good.
Sync play is TERRIBLE with android TV. We tried watching a show over sync play on the LAN in two different rooms and it just constantly lost sync, commands didn't go through, etc. It was so bad we only tried it once.
Controlling the Android TV app from Jellyfin Mobile or web is awkward at best, basically unusable.
The other thing to check is your transcoding setup. Sometimes the settings are not optimal and can cause playback issues.