Portable player/storage Device/ Replacement for JRiver?

I am a portable digital music Noobie, but have a JRiver MEdia Center (21) (all FLAC files) set up on my Windows home system.  TWO unrelated questions, please:

1.  I would like to buy a low- or medium-priced portable device that will store and play FLAC files that I can simply copy from my NAS drive.  My listening would either be straight out of the device on headphones, or plugged into my auto sound system.  (My stock auto system does not decode and play FLAC files.)

2.  I chose the JRiver (21) Windws system 2-1/2 years ago and, once I was able to got it to operate without problems, it's sound quality was and is excellent.  But for only a semi-savvy or non-savvy software person it was a painful process.  What is the predominant opinion currently?  Is there software that offers the same SQ but is much more user friendly?  I realize Roon was gaining popularity quickly two years ago.  I am not currently streaming music, but may want to do so in the future.

THANKS MUCH.  Good New Year wishes to all.