Most Griffs usually alert the family by barking when someone comes to the door. All breeds have some genetic problems. This is an inherited abnormality of the hip joint that can lead to problems later in life. There is no way to guarantee that you will not get a puppy with hip dysplasia, but you can increase your chances for good hips by making sure both parents have been OFA'd. This depends on your personal preferences and what you want in the personality of your dog.
Females are also mellow but are more likely to test an owner to see how much they can get away with.
Puppies are really, really cute, but if you don't have time to devote to training and socialization, you owe it to your family and the dog to get an adult instead. If you have very young kids, an adult is probably more appropriate for you until your children are older. Normally, a Griff who is given proper care, nutrition, and exercise lives to about 12 years of age. With luck, they can go to age 14 or 15. A Griffon's prime is about age 4 to 7.