My understanding is that the N100 definitely relies on having an external NAS where all the music resides. The N100 has a relatively small internal solid-state disk where music is pulled into the SSD cache over the network from the NAS... apparently to help minimize the potential for audio drop-out on a less than ideal network.
The X100 has internal SSD cache as well as much larger internal disk drives so all the music can be local within the X100 box, but it too can use an external NAS but it's not necessary.
The key question then is whether the music within the X100 can be shared out to other client devices on the network. I would think so, but maybe I'm assuming too much.
The only difference in these two diagrams is that the X100 shows the NAS as "optional".
N100 setup
X100 setup
