I've heard that if you want a puppy/dog with good behaviour from the get-go, You should definitely purchase a pure-breed.
The cross-breed that we had about 10 years ago (We named her "Angel" but she was anything but...) was always up to some sort of mischief but our pure-breed Maltese Terrier (who we've had for the past 6-7 years) has never done anything wrong
. (Of course, not all cross-breeds are badly behaved...)