That's because it's (or at least was) a nightmare to setup in the first place, plus the interface was very basic/limited. That said, I haven't used it since NZBDrone was very early released and haven't looked back. Sonarr is awesome on mobile, SB was woeful. At the time, it was a no-brainer to swap. Took me couple hours to setup NZBdrone initially. SB took me over the course of a couple nights. CouchPotato used to be horrid too, it used to pick up either CAMS when they were filtered and never had very good controls over filesizes either. I used it again recently and it's miles better than it used to be, but I did convert to Radarr as I really like the consistent interface of Sonarr/Radarr. Radarr still needs some work, but I'd say it's at least on par with CP at the moment - at least the way I use it!