>>82398142mumei's voice is very sweet i love how it can stand up in very instrumentally simple songs, which is her trademark.
Suisei is great obviously yeah, technically masterful and she gets some absolute top tier producers working on her stuff
I put Kanata up there as high as Suisei or even more, she's one of the best vocal performers out there and i love her taste and choice in covers, she also dabbles in production herself and is famous for her infinitely high range
Polka is my oshi so I'm biased, but she has to be highly rated for her range and adaptability, she can do literally everything and always brings incredible passion and emotion
i really like Noel as the other anon said, she's very cute even if it isn't textbook technically perfect. her karaoke and songs are great. it's like she cares way more about sounding out each word clearly, more than timing or tune, its very unique.
Laplus has insane vocal control and an awesome tone to her voice, really cool song choices often brings something different like from EDM to a retro soul tune.
Watame's karaoke is fantastic and her songs are pure joy. she has great taste, so many bangers every watame night fever.
Towa is up there ofc, she's powerful, really gifted, and i think she's one of the most seasoned singers in hololive as she was great even before joining, her lower range brings something different from most holo singers and usually goes for a more metal sound.