The English Mastiff and Bullmastiff are two breeds who each make excellent family members for the right family. The older of these breeds is the English Mastiff.
The mastiff family is ancient and ancestors of this family go back to the time of Rome. The modern English Mastiff is more recent; the breed as we recognize it was standardized in the eighteen-hundreds. The Mastiff has long been associated with English landowners, a handful of whom were responsible for standardizing the modern English Mastiff.
Gentle, loving, and huge, the Mastiff is devoted to their family and does well with all members of a family, human and animal. While they take up a great deal of room they require only a moderate amount of exercise. This is a very laid back breed of dog whose personality no longer bears any resemblance to the dogs of war and fighting that their ancestors were known for.
The Bullmastiff was bred from the English Mastiff with some influx of Bulldog blood; approximately 60% Mastiff, 40% Bulldog. The Bullmastiff was designed to be a more vigorous, active breed than the Mastiff, without having as much fighting instinct as the Bulldogs of the time. These were guard dogs that could actively patrol with the men they accompanied keeping the grounds of large estates. Mastiffs were guard dogs for the courtyard outside an estate's home, Bullmastiffs patrolled the grounds surrounding the home.
Bullmastiffs are also an excellent family dog, good with all members of a family. The biggest difficulty with them is that as young dogs they are rambunctious and likely to knock over very small children. They do require more exercise than the Mastiff as they are more energetic and active. One thing these breeds have in common is a heavy jowled face that has a tendency towards drooling. People find it handy to keep wipe cloths handy with these breeds. The personality of both these breeds has been gentled over the generations and both are well suited to being happy family members. Bullmastiffs are less likely to be as accepting of other animal family members than Mastiffs.
The drawbacks to these breeds are mainly health related. Dogs this large will eventually have joint problems - hips or elbows. Major organs are also more likely to give out over time, particularly the heart. Finally, it is possible for either of these breeds to develop cancer as they age. Perhaps because they have such an influx of Bulldog blood, the Bullmastiff is actually even more prone to health problems than the Mastiff.
It is the slightly smaller but genetically more troubled Bullmastiff that is likely to have a shorter lifespan, reported to tend towards a span of 8 - 10 years, while the Mastiff often reaches 10 - 12 years. Given their size this is a longer life span than one might expect in a giant breed.
As always, both breeds, and crosses of these breeds, are available through breed rescue and can also be found in shelters. Mixes of these breeds are becoming increasingly common as giant breed dogs are enjoying a surge in popularity.