I never liked Hebi Sasuke. That stupid, lazy look in his eye, with no expression or emotion. His emo style, and boring character "development" (he went from being a dynamic character to being a lame carbon-copy of every stoic, brooding anime character).
Adult Sasuke is perfection. It's the first time since Part 1 that I've truly been able to respect Sasuke's character. I liked him as he developed in the War Arc, progressing away from the abomination that was Kage Summit Sasuke. However, Adult Sasuke is just a total badass. Perfect combination of wisdom, compassion, and cold logic, with a sweet moveset. Plus honestly, losing his arm just upped Sasuke's "badass factor." The fact that he limits himself to one arm by choice, despite having the option to gain a Hashirama arm, just makes it cooler.
However, I will say that Adult Sasuke has the worst hair of the bunch. I wish it was either longer or shorter; not a fan of the emo slice over the Rinnegan eye, with the hair down in the back rather than spiky. I get that Kishi wants to give his new generation of ninjas a more "modern" feel, demonstrating that they're progressing away from the era of warring states and whatnot... but that doesn't really apply to Sasuke, who I view as someone who will live and die as a model of the "classic" ninja.