The problem will be playing FLAC format, but otherwise an iPod makes the most sense. SQ is one of the best for portable devices and better that most smartphones.
In fact I use my old 4th gen iPod Touch for YT videos instead of any of the smartphones or tablets (both Android and Apple) that I have at home. iPad is extremely limited for music, the iPhone does a decently good job and most Android phones and phablets suck... but the iPod still sounds the best for YT videos or when using a dock. I have simple iPods too (the non-touch varieties) and their SQ too is way better... but again space is premium unless you are talking mp3 rips.