I was told by a breeder once that blue and golds make better pets then a scarlet. Scarlets, from what she told me aren't as cuddly, and can be a bit harder to handle.
I agree, with the research that I have done basically says the same thing. But from all the species, Greenwings are more laid back then most all of them. Although they are bigger, they are said to be more gentler and a bit quieter than the rest. Also, Red Fronts are another to consider, if you can find one.
But you must realize, no matter how much research you do, it's mainly up to the bird you choose and YOU and to whether the bird will be a good bird or one that is hard to handle and noisy. All birds have noisy times, which can be exagerated by the owner, who can spoil the bird and cause them to be needy. I know, I have spoiled my Little Senegal rotten and she lets me know it all the time.
Birds the size of a Macaw are always best to get at a really young age so that it will be easier to bond with them. Rescued birds will come with a l,ot of baggage that you will have to overcome in order to begin to form a bond with them. Most if not all have been abused or neglected and cage bound which causes aggression & plucking.
You could also consider one of the Hybrids like a Catalina, which is a mix between the Blue & Gold and the Scarlet, but with a much better temperment.
But to me, this would be my list of Macaws:
Greenwing
Blue & Gold
Catalina
Red Front
Military
Scarlet
But lets face it, when ever you think of a macaw, everyone always thinks of the Scarlet because of their beauty. But they also are harder to handle then the rest. But again, that is also up to the individual bird.