I am currently looking for USB audio interfaces to act as a USB DAC/amp and for future recording. My choices are the M-Audio Fast Track Pro, Focusrite Scarlett 2i2 and the PreSonus Audiobox 22VSL. Which of the three is better in terms of driving capability and DAC performance? Headphones used will be a Hifiman HE-300 and an Ultrasone Pro 900 (which I hope to acquire soon).
The Scarlett is the cheapest of the bunch, and also comes with a less feature-filled suite than the other two. PreSonus and M-Audio's suites are great, but M-Audio comes with the best, IMO, due to inTone adding virtual instruments.
However, my top priority would still be the dynamics of the headphone amp and the DAC section. Which is better among the three?