OP, based on what little I've read about the JH-3A, I've no doubt the tech will make most anything sound great. 3X0 has a very valid point, however--it's probably much more trouble (and money) than it's worth to set up a great portable rig.
FWIW, I see the key things of a portable rig being:
1. Isolation - without which one can't concentrate on the music anyway
2. Size - depending on what bag(s) one carries, a rig that's too big is a disincentive to lug around
3. Battery life - the last thing one wants is a fantastic setup...that can't work.
But the most important is probably isolation. With more of it, one might say that sound quality improves or is more easily appreciated, and either way, this amounts to more bang for buck. However, since isolation is rarely perfect, squeezing the last inch of perfection in sound quality out of a portable rig usually incurs hugely diminishing marginal returns.