Interesting article...I'd be curious to see those tests run again using Android phones like the Nexus 5 and G2X with software like Voodoo and Faux Kernel installed that give manual control over analog and digital gain to see what their actual impact on measurable aspects of SQ is. I notice that the N5 really runs into most of its problems at high volume, which comes from stressing the amplifier and not maximizing the use of digital volume control. I can hear audible differences using Faux Kernel with the analog gain taken all the way down: noticeably less distortion which leads to improved sense of instrument separation, more realistic imaging, and an overall less "blurry" sound.
This article offers many interesting details about smartphone audio quality, with measurements for the Nexus 5 and the LG G2.
~Brian