Some Cockatoos are not destructive and other Cockatoos are obedient, contrary to the tendencies identified here. Cockatoos are the only parrots with crests. Crests are used to help them express their thoughts and communicate with their flock and with us as extended flock members. The dust sometimes irritates allergy prone folks. A Cockatoo bite is said to be worse than any other parrot's as their lower beak has 2 points, resulting in a 3-point bite if delivered.
Cockatoos scream very loudly.
Be sure all members of your family are willing to tolerate the twice a day scream of the Cockatoo. A Cockatoo loves to laugh and sing and dance - with you is preferable. Without you will do, too. Their joyful demonstrations are loud and can cost them their homes. Attached is a picture of my Umbrella cockatoo dancing and singing.