I really thought about getting a spider monkey for like 2 solid weeks, did all the research and looked through as much as I could find. end result......DON'T DO IT. They are exactly like children, need constant attention, get very noisy if board, also destructive and really enjoy playing with the poopy that is never ending out of their bottom.
Not to mention that young spider monkies are very cute, but an old spider monkey is very unattractive.
If you don't give them constant attention they start to get isolated and it becomes harder and harder to get them to be nice after that. So unless you have the schedule that allows you to pretty much keep a kid around all the time with you, I would suggest a different pet.