One important consideration is that unlike plex servers, it’s totally feasible to throw your entire library on a single device. Another important difference is

One important consideration is that unlike plex servers, it’s totally feasible to throw your entire library on a single device. Another important difference is that these devices are not pervasively connected to the Internet. Koreader comes close, with comprehensive stats tracking and progress sync, but I absolutely would love to see SRS or stronger note taking or easier content management