actually amarbir,have yet to see the insides of either,for now only pics of the hardware

.honestly speaking the sflo2 is impressively specced no doubt but how does one ignore the options(cowon,etc) with the sflo2's drawbacks??hell,i was even on the verge of getting one.
The prob is as u said and i have always maintained,that its inevitably the implementation of the said dac chip thats does the magic.case in point is my keces da 151 mk2 usb dac.it uses a burr brown pcm2702 chip which has so many documented limitations(manfr admitted)and yet it can sound so clean.good stuff.
Here also,its the overall package that wins hands down,and to even worry about the documented battery life and interface issues have me in the cowon camp

.cheers