Please note that I don't have an Eikon or Atticus. My experience is with the HD800 and the Blackwood, and I prefer both with the Project Ember, but not by leaps and bounds. Also, the sound of the Ember is tube dependent and I'm using dual Zenith 6J5G tubes that cost ~$100 when I bought them + $15 for an adapter.
I find the sound of the Violectric to be actually darker than the Ember with my tubes, and also not quite as clear and detailed, nor as dynamic sounding. To be fair, I don't dislike the sound of the Violectric at all, and I could definitely see others with different tastes preferring it. I'm not put off by bright sounding treble, as can be attested by the fact that I prefer my HD800 unmodded (although I do use EQ to tame the treble.)