The way I do it is bring my Nighthawks and/or favorite headphones to meets/Can Jams and listen myself. Most are very similar but only two have "stuck out" as being "outstanding" or "jaw dropping"
and clearly different from others.
One is the Audio Technica ATH-5050: http://www.head-fi.org/t/749555/sneak-peek-of-audio-technica-at-ha5050h-pre-production-unit which is not out and may never come out and when it does come out it will be $6000+
The other is the Headamp GS-X mk2: http://www.headamp.com/order/index.htm which I dunno what's going on with them, I saw a red version at two meets, Can Jam London and Axpona, but it's not on their web site. Also no description of the "mk2" version and no photos.
Anyway, nothing from Schiit has ever impressed as anything sticking out from the crowd, including their TOTL Ragnarok. I want to be blown away by the Cavalli stuff as everyone keeps saying it's the best, but when I listen at meets on my own headphones I'm not getting the magic everyone talks about. I've listened to the Liquid Gold, Liquid Crimson, Liquid Glass, and even a prototype of the new Liquid Tungsten didn't impress. I have Liquid Carbon which sounds excellent. Headamps Blue Hawaii also blah. Also unimpressed by Chord's "Dave" amp which cost 10k+.
I always take a backpack with at least 3 headphones to test; at Axpona I brought Ether Cs, Nighthawks, Sines, and HD650s.