This is what my ASPCA dog book says.......
Peks are playful and very loyal. Some Peks are stubborn and independent, making obedience training a challenge. They are cautious of strangers and are not fond of children under about ten. While they can be aloof or aggressive with other dos, they are usually good with cats. They can be alarm barkers, alerting the household when visitors arrive. Pekingese are suited for apartment life, especially with an adult household.
My grandmother had one when I was a kid. It was down right nasty, but it was not socialized properly. She also babysat a pekingese and he was not friendly either. Again, probably not socialized well.