I adoped a little mixed bred dog from and animal shelter five years ago when she was about six months old. She has been the nicest dog I've ever had. I really believe an adopted pet understands they are getting a second chance at life and are far more willing to do what you ask of them. All it takes is patience and a lot of love from you.
Another advantage of having a mixed breed is they tend to have fewer health issues like some the pure breeds do.