Strange, how whenever the name Bullmastiff comes up, there are quick responses that seem to somehow put out the fire before it has even started. With all respect, Vinay(bullmol242), I totally understand what you are saying, I respect you as a breeder, and have always commended you and still do to this day. What you say is very true , that the Bullmastiff has been 'watered down', but, I firmly believe from my own experience, that there are truly outstanding specimens, who will guard and protect in many different situations, while still very young, and above all, with no formal training. From what I have learned from Bullmastiff owners from the the US, is that they have far less drive, than the Bullmastiffs in the UK. I think, personally, that whenever, such a question is posed, people will take it personal and try and promote their dog of their country. I am speaking from experience, and can honestly say, in reply to Cornelio, the Bullmastiff is a great guard dog, fantastic with children and babies, other pets, if introduced when young, and require basic exercise. With regards to life expectancy, it all depends on genetics and how well you take care of your dog. I got to meet my dogs grandparents, parents before we bought our Bullmastiff, and they are still alive and well. I really think generalization is a bad thing, just look at the AMERICAN PIT BULLTERRIER, so many bad things said about it, and its a great breed of dog. There are bad lines out there, and there are good ones. I think this can be argued about a lot of Bully breeds. This is just my opnion from experience.