I have both units. Tested the Gungnir balanced into an audio-gd master 8 v. the HA1, both fed by USB2, both fed into HD800 SE, OPPO PM1 balanced, or HE 560 balanced cans. I did not test the OPP DAC into an external amp because I don't think I would every use it that way.
After several days of casual listening I am unable to find any significant differences. The HD800 and PM1 sounded identical in every aspect, except when I drove the amps up to to ear-bleed levels. On the 560, the Gungnir\audio gd combo tamed some of the treble spikes slightly better, but only slightly. Don't know if that was the amps or dac though. If you put me blindfolded in front of the systems I couldn't tell which was playing. Sacrilege, I know.
... HA-1 supports DSD in native as well DoP mode while Gungnir doesn't support it at all, yes they may add it in the future but definitely not for free. How many DACs support DSD in native mode? I heard about few, but can't remember their names, but they cost way way more than HA-1. ...
The lack of DSD I did notice. I have enough DSD tracks that it became annoying to when switching between the units, and Schiits answer so far is the un-balanced Loki unit, so the HA1 wins there.
As far as other native mode DSD playback units, the Mytek Stereo192-DSD, Yulong DA8, and Benchmark HGC DAC2 are all balanced and out there, the first two at comparable price points. More units are supporting DSD every day.