Like magister et. al, I have it both ways also. I have a QNAP NAS, which is in my home office where my router is located. All of my music is stored there serving as either a primary or a backup role. I also have a Mac Mini with the same music library on an external HD, connected via FW800. The Mac Mini is physically connected to my PWD via USB as well as through a CAT7 cable in my listening room.
I use JRMC and can load up the library from either the attached HD or the NAS. I stream over my network to the BII or use the MacMini as the player via USB. I control via JRemote on iPad. I find the BII to be better than USB in dynamics department. I don’t have a jitterbug or Regen on the this system so it could be they would bring the USB up to BII. One of these days I’ll give it a try to see.
Using the MConnect iPad app, I can access the files directly from the NAS and play them through the BII, although I give up a ton of library functions. I can’t say if there is much difference in sound quality streaming straight from the NAS versus using the mac as the streamer because I haven’t sat down to really listen to them critically. I like the library management functions of JRiver/Remote so even if there was a SQ difference, I might still use them. What I can say is that both sound terrific in my system to my ears.
I don’t have any high end USB or ethernet cables. The price of entry is just more than I want to swallow, compared to a Belkin Gold, etc. YMMV.
However you approach it, you are still going to need a computer to rip files, manage libraries and metadata so you won’t be eliminating the need for a computer, just removing it from the audio chain. I say, if you find a library manager/player that resides on the NAS that you like, it makes total sense to do so. I just haven’t quite got there yet, but I’m hopeful.