The first three platforms rely and run on server-side software. Infuse is a stand alone client that must manage everything within the confines of the Apple devices to which it is installed and Apple developer software.
For those who need the services provided by Plex, et al., they all have client apps and Infuse can also serve has a hybrid-client.
Custom collection art for custom collections is said to be coming very soon. That will definitely improve things greatly.