Hi Don
I am owned by a lesser-sulfer, a female umbrella, and a male umbrella. The male U2 came from an abusive home and has bonded to me and me alone. No one else is allowed to hold him and when he bites he does not let go. For me he is the sweetest baby and a cuddle bug. My lesser-sulfur we call little britches. He won't stay in one place for long and isn't a snuggler at all. The female is the sweetest of the bunch - she is a great talker and was given to me by a dear friend. I am also owned by a B&G macaw, a quaker, and a sun conure. Of them all my favorite is the cockatoos.
As Cindy mentioned, it really depends on how much time you are willing to spend with the bird, and the type of attention you are willing to give it. Mine are all pretty well-adjusted and will play by themselves well. But they do have that time where they want to be held and cuddled.
Another good point that Cindy made is the destructive side of the cockatoos. My umbrellas chew everthing and anything in sight, and buying toys can get expensive. Heck, I spend more on them in a month than I do myself in a year!
Hope this helped a little.