Hello MinkFeathers,
Being an owner of a sun conure, please allow me to add to your conversation
Firstly, I must say it's awesome that you are putting THAT much thought and research into your choice of bird! That's amazing and will save you from any "surprises". Now for the sun conure part. I absolutely LOVE my little guy, Lemon. He is everything I can ask for and more! Fun little clown, smart (has learned tricks in minutes), cuddly, doesn't bite, not a one person bird, and beautiful to top it off. If you ever own your own house I would definitely recommend a sun conure. I love them! However, in an apartment, I just don't think it would be a good choice. Now, Lemon rarely lets out that patented shrill sun conure call. However, there is almost always at least one person home and he is rarely alone in the house. He is right in the living room, cage door open when we are home and usually with one of us watching t.v., etc. when we are home anyways. So, he is with his flock and content. He will only call in the morning when he hears someone is awake upstairs and also when we come home (like a guard dog lol). Literally calls less than 5 minutes per day. Actually maybe a min or two. He is not a "screamer". However, remember that you are the one that chose to have a pet bird. Your neighbours did not. If you get a sun conure (or relative), unfortunately, there is going to be times where your neighbours will feel like they are living with a bird lol. As some other members have said, it's better to not risk having to rehome him and set yourself up for success to begin with. Parrotlets, budgies, lovebirds, cockatiels (if you have no allergies) I think are great choices. I think a cockatiel would like nothing more than to chill on your shoulder all day. A hand raised one of any of these species would be ideal of course although I owned a pet store budgie for 13 years that was as tame as could be and NEVER bit me not even once! So, your experience will be varied. Just like with snakes...sure ball pythons are reputed to be gentle but you CAN get a nasty one!
Like I said, if you ever have a chance to get a sun in the future don't hesitate because I'm sure you will not regret it. As long as the environment is right for you and him/her I think they are great birds!
I hope this helps you in your decision!