Its very portable, very small, good battery life. Combined with an Apple product you can use it as an amp, with some Androids, a pc or mac as a dac as well.
I have little experience judging sound quality, but for me it did a good job on my iPods. Especially since I have European volume limited ones and headphones needing some more juice.
As a dac it sounded a bit better as the built in dac of my laptop.