Honestly i think people greatly exaggerate with Sasuke's mood changes. Sure, he switched around a lot but i think all of that was properly explained in the series and actually made sense maybe outside of him randomly wanting to help the village in the end. He was manipulated by Itachi and then Tobi after all.
Dude's edgy but sometimes i like that lol. Zoro to me has always been a cheap rip off of Guts or Kenpachi. He's only ever being compared to them and never actually the real thing.
I prefer Sasuke for sure
Nah, they don't. After Itachi's death, Sasuke became an emotional wreck - on negative terms. As I told you, after that he was an emo edgelord driven by his daily periods and his goals were all over the place. After meeting Tobirama and Co, he decided to be the next hokage...
Part 1 Sasuke & Early Shippuuden Sasuke was not bad (still better than Naruto) but afterwards, it was just cringe with him.
I don't understand why people compare Zoro with Guts or Kenpachi in the first place? Zoro is his own character: his sense of direction gags, Zoro mostly showing various emotions on many panels, even battle related, and sure, Post-TS Zoro has more of these "badass battles" but he still is his own character not entirely based to be badass. Remember when he used Usopp as his sword? Even after Wano, Oda wrote a funny moment of the strawhat crew roasting Zoro.
That's why I don't understand these comparisons. Zoro has badass-traits - that's true. But he totally links with the atmosphere of the manga; badass but clumsy, funny, idiotic and other characteristics defining what's about One Piece.
Zoro is just way more enjoyable than Sasuke will ever be. It's not hard to judge who's a better character imo. At the end, everything is subjective regardless. :)