Recently, I installed twonky pro on my dlink nas dns320 and 320L. Twonky is better than the default one from dlink. Now, twonky supported subtitle stream from my nas.
So, if DLNA streaming is what you are after, nas plus twonky may be a more economical and versatile solution.
On pc, you can use more sophisticated stuffs like xbmc, but it's more clunky and you still need your pc to host the file or store them in nas anyway.
My set up is twonky as DLNA server on nas.
Skifta player on android gadgets from android tv boxes to tablets or smartphones.