Wavelength Cosecant USB v3 vs Benchmark USB DAC1

Now that both the Wavelength Cosecant USB DAC v3 (now with ASYNC mode) and the Benchmark USB DAC 1 and DAC 1-PRE support 24-bit audio at sample rates up to 96 kHz without the installation of any drivers or other special software. I am having a hard time choosing between them. My primary headphones are the Ultrasone UE 9 and the Grado GS 1000. Has anyone out there heard both side to side at any of the meets??? Are there specific advantages of one over the other?