Both Aurender and Lumin get great reviews. My Audio Research dealer carries Aurender. I have not had a chance to hear the Lumin. After some research I have come to think that having a hard drive is important. A streamer that plays from a NAS, needs to be hard wired to the network so that it performs it's best. This is especially true with high resolution (24 bit) files. Otherwise there can be errors and the music can sound choppy at times.
A streamer with a hard drive plays off the hard drive. So there is no "real time" performance problems. You can control the streamer from an Ipad. Plus having your music files also stored on the streamers internal hard drive is like another backup.