Well I was pleasantly surprised, before we got our Sun Conure (Bailey), I was led to believe they screamed bloody murder

With Bailey at least, that isn't the case at all, sure he does have his moments and it can be quite loud, but it isn't for long, it is only for 3 minutes at the most. But it is only when we have been out and come home, he is simply saying hello, it's about time you got back, he also does this first thing in the morning when he sees us, again, this is his greeting.
I really think it depends how you treat your bird, Bailey has the run of the house when we are home, he has lots of toys to play with including foraging toys. He also gets to spend a lot of quality time with us, either just chilling or playing and training.
He also gets "time outs" in his cage, but again, he has lots of toys to keep him occupied. He has a good mixed diet with various fruits and of course small treats throughout the day, all this goes toward keeping him happy and content.