I love that you are taking the time to ask such a good question. I have 2 greys and got a 6 month old yellow crowned amazon on a whim. I knew nothing about them and am glad now that I didnt, if I did, I would not have gotten the love of my life.
My amazon's named Nilah, there are many threads posted here about her and her antics.
Can she be loud and animated? Yes.
Does she scream? Never, only when my daughter died my dog pink! There is a video here showing her dislike.
When I am having a loud conversation, she will too.
When I am quiet, she is too.
She loves to sing, one of her favorite things to do is sit in the windowsill and sing.
She has no reason to scream, I talk to her a lot, so she will talk instead of screaming.
She does not whistle like a grey, she prefers to sing opera and talk.
She has captured my heart in a way that no other bird or pet has done. That's what makes an amazon so special.
She is 5 years old now. She is very smart and can try my nerves when she makes her mind up to, but I learned right from the start, never to let her win, I only let her think she wins and that makes her happy and easier to work with. She is very bonded to me, we are inseperable when I am home. In fact, as I am typing this post with one finger on my iPad, she insists on perching and preaning my other hand . This is how I spend every night while here or watching the tv.
So as long as you understand what you are in for (they can be very difficult when they get hormonal)and are sure you will be this amazons forever home no matter what, then you will never regret the love of an amazon!
Oh and one other thing, their bite is very different than a greys. A grey will slice like a knife, an amazon is more like a vice grip....but never let them no it hurts, just say 'no biting' they get it....