Green Cheek Conures are one of the quieter Conures, BUT that isn’t to say that they will be quiet all the time.
Admittedly, my 2 Green Cheek Conures are my fourth quietest birds here (Bourke first, Budgies second, Cockatiels third), they can get a high pitched scream/squeal when they are excited though, and it can be ear-piercing if you are standing close enough!
Otherwise, they are fantastic and wonderful little birds — they are like a Macaw, only they have been put into a little body, and turned into a little bird, they even have the big birdie attitude.
Another thing is, my 2 Green Cheek Conures are completely different from each other. Leila, my Cinnamon Green Cheek Conure, is the more clowny one, she hangs up side down off of the top of her cage inside, she hangs off of my finger, she hangs off of pretty much anything, she lays on her back in my hands, she loves being with you (she is a tad clingy), and she loves, loves, loves scritches and is total dork when she does her favorite thing, which is dancing.. she also rolls over like a dog which I taught her.
Taji, my Yellowsided Green Cheek Conure, doesn’t do anything like Leila does, he is more the type that keeps to himself, and just loves being on people and being given attention.