Abyss AB 1266 Phi vs Focal Utopia

Pretty much every reviewer mentions just how well built the Focals are. Also the Abyss 1266 is indeed quite a bit more difficult to drive than the Focals. It's something regularly discussed on Abyss threads. Focals are 104 dB efficiency and the Abyss 1266's are 88 dB efficiency.
Good luck!

https://positive-feedback.com/reviews/hardware-reviews/focal-utopia-abyss-phi-cc-hifiman-susvara/

When I was in my headphone phase, I owned both the Abyss AB1266 and the Utopia. I don’t know how much better the PHI is. At the time I preferred the Utopia most days, but the Abyss was also excellent in its own right. 
Don’t know if you can go wrong. They are both great for headphones.

Utopia for a more all around boring clinical yet technical sound.

Abyss for a more exciting in your face high energy kind of sound.

Though worded as if Utopia is not as good, they are both good in their own right. Depends what you are looking for.

If you can demo, that is best, if you can not, consider the gear needed as well, Utopia needs less powerful amp!

All new Camerton Audio Binom-ER headphones are out now

 They sell them in the USA now