I've been using Google Music, and used to love it. I have it maxed out at 20k songs or whatever it is, but the last few months it has sounded like absolute ass when streaming it. I get crackling in my speakers from too much treble or something, which I've verified isn't my speakers' fault, and a Google search indicated lots of other people are having the same issues.
And while I certainly can't hear the difference between FLAC and the (I believe) 320kpbs that Google downgrades it to, that negates the backup issue for me because I keep pretty much everything in FLAC.
I've screwed around with the DS Audio app and it actually works flawlessly and fast via wifi here at work, so I'm guessing I had shitty 4G connection or something when trying it in my car. That would probably cause the same exact problem with PLEX, but I might try it out to make sure. The only downside to that would be that, right now, XBMC is installed on my HTPC, which I only turn on when I want to watch TV. I'd have to figure out how to get it permanently on my NAS, or leave the HTPC on constantly, which I'd prefer not to do. I'm just fairly clueless about installing anything that isn't Synology-provided on my NAS.
I'll do some research I guess, and definitely check to see if it was simply a 4G/3G problem originally. If that's the case, the app works well enough to not worry about fucking around with anything else. I wish I could stick with Google Music, but right now it fucking blows for me, even deleted the cache, turned it to high quality, etc. Until they fix their compression algorithm or something, I can't stand listening to it.
Thanks for the advice.