Used to have Apogee Groove more than 2 years ago when they just came out... Did not work out for me, I found it's sound to be quite a bit bloated and undefined in low end, made me understand term 'one note bass'. Surely better than built in dac/amp in most everything, but I found that Beyerdynamic A200P worked out better for my portable needs (more neutral, more honest, does not over-exaggerate bass, has built in battery). I would not say that A200P is perfect (wolfson dac is a little on warm side, not very detailed, and soundstage is pretty flat), but it was/is a good compromise for me between portability and sound quality, and its sins are mostly of omission. Apogee Groove was not my cup of tea - its sound walked a bit too far from my idea of neutrality and precision. It just tries to impress too much, and turned out to be not great for me in a long run. Funny thing was that Apogee Groove worked quite well to elevate cheap IEMs to semi-reasonable performance level, but with better headphones it just did not do too well. I find that marketing image of a guy plugging in Senns HD800 into Apogee Groove to be quite hilarious... it sounded not so hot with HD600, why would somebody waste HD800's potential on that setup? Keep in mind, it might be just that I do not like sound of Sabre DACs, never found one I liked, always prefer Burr-Brown 179x family.