For vocals, i find Variaudio (3) pretty good, and i like it’s ease of use - in most cases, since version 3 it gives me a more natural sounding result vs Melodyne - but that’s very subjective and dependant on type/quality of vocal.
Plus if you spend time to construct the project with chord track entries it ties really nicely in to the colour grading and general integration on a whole (Vocal align, and Harmony Generators).
I only have Melodyne Assistant (Upgraded from the free version of essentials you get with Studio One Pro license) to compare it to though, the other versions start to cost the same as Cubase Pro on it’s own… so it’s a consideration for those on a budget looking at Studio One vs Cubase.
However, the fact remains that Cubase has it’s own engine developed in the same period that Studio One was developing ARA, they took a different path… but soon (2022? lol) you will have the full advantage of both. Never tried revoice.