So much ignorance in this thread.
The American Bulldog, like most other dogs, can be a great companion. A properly educated and loved dog will never be a threat to your family or guests!
That being said, you already have a pack and there's always the chance one or more of the other pets will reject the new dog. This can be corrected by an assertive, experienced owner but no always so, just like people, pets sometimes just don't get along.
In example, my Malamute, despite training, good behaviour, exercise and regular contact/play with other dogs, hates sharing my family's attention. He is very friendly with other dogs during walks/play, I've never seen him initiate aggressive behaviour yet when other dogs visit our home he displays jealousy and he becomes very possessive. Given long term exposure to such a scenario, he may even become aggressive so we will never get another dog.
My advice is to get the dog but take good care of him(or her), train him and constantly watch for behaviour issues in the puppy's first year or so. If your pack adopts him, he will be a great addition to the family.
