The only legendaries it beats are those with the highest impact rating. And I believe that archetype is specific to year one (maybe, but not certain). Otherwise every other legendary with a semi-decent roll will out perform it. Hawkmoon CAN two shot, but the occasions are so much more rare than a regular LitC Eyasluna Archetype. But ultimately, it's up to you as to what you prefer. Many prefer the legendaries over Hawkmoon for performance purposes as well as the ability to use another Exotic.