Abyss AB 1266 Phi vs Focal Utopia

The Abyss are a little more "speaker like" in presentation. The Utopia has a smaller sound stage, but imaging is still very good. The Abyss is a little more accurate at resolving midrange...while the Utopia has outstanding treble resolution. Although the Utopia can resolve different styles of bass with accurate tonality, tonal changes do occur when things get complex. So if I were you, I would go for the Abyss. The Utopias are also kind of fragile...unlike the Abyss which is literally a tank in the form of a headphone.

They're both easy to drive with a decent headphone amp. No need for lots of power like the HiFiMan HE-6s.

Hope this helps you choose.

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.