The Plexpass need only if you want to make other people's libraries available, which is a nice touch. One logs on, paid the Plexpass and the others can be invited after registration and have access to the shared libraries. Easy you can currently his film and photo collection of his family did not make available.
When using the Plex Media Center you can use with the Plex app the phone / tablet as a remote control.
Another nice feature: As the owner of Plexpass can I download my media after registration elsewhere.
For the other users is not possible. There are slow Internet lines go another feature: sync. Man looking off what movie you want to see later, selects the sync from the quality and the server has been minutes much to do with the change of the video. Daskann you then view the move as long as you have an Internet connection that is needed to log in to Plex.tv. The film itself is then already on the device and no longer burdened the Internet Budget.
For me it is quite clear the access of several people on my favorite libraries, have friends / relatives quickly access the Home Videos and domestic photo collection. The Plex app unfortunately is not that great either. the Plex Media Center is gone forth from time XBMC, unfortunately there is not the beautiful variety of skins from XBMC.
I use otherwise prefer Kodi / Yatse. :)