The QLS QA350 sounds better than the S:Flo2 and is slightly under the HM-602. it cost $200. However, the QA350 has digital outputs in both coaxial and optical forms, so you can hook it up to an external DAC that is either desktop or portable. Something like the Ibasso Boomslang and Toucan portable DAC and balanced amp combo would elevate the sound quality to slightly under the HM-801, while being able to drive almost any headphone ever made with authority. I have the QA350 and the S:Flo2, so I know how those stack up for certain. The QA350 is huge and only take SD cards for memory, something you might want to keep in mind. I love it though. The rugged build, the actual knob to adjust volume, the speed at which you can flip through your SD card full of files, it all makes for a fun musical experience. i can personally vouch for the coaxial output's quality, as I have heard it through some high end equipment and it sounds fantastic. It is just as good as a lot of CD players with digital outputs.