There are a number of other breeds in the mastiff family.  Such as the Bullmastiff, Neapolitan Mastiff, Fila Brasileiro, Tibetan Mastiff, and Spanish Mastiff.  These are recognized breeds.  They have been established for MANY years.

The "American Mastiff" is not a recognized breed of dog.  It is a mixed breed.  It is part Mastiff and part Anatolian Shepherd.  There are NO health testing records behind this mix to substantiate the claims of better health.  The natural temperaments for the two breeds that were combined to form this mix are complete opposites.  This can be and has been a dangerous combination.  And they do NOT look just like a Mastiff.  Yes, there are many happy 'customers' of the "American Mastiff" breeders.  You are bound to have some when enough quantity is produced.  But, there are just as many unhappy 'customers.  The claims made by these breeders have no factual foundation.  The Mastiff community has had to pick up the ball when these dogs do not turn out.  When they are aggressive.  When they drool and the people were assured they did not drool.  When they have health problems.  Etc.  Their own breeders have NOT stood by them and the puppies they have produced.  These dogs claim CKC registration.  Do NOT be fooled!  This is NOT the respected Canadian Kennel Club.  It is a 'knock-off' called the Continental Kennel Club.  All this club requires to register ANY dog is the signature of 2 people (any two people...pick two off the street) to agree that it is what ever breed (make up a name...they don't care) and 3 pictures (front and each side).

There is not and never will be a perfect breed of dog for every person.  Each breed of dog has the traits that make it unique.  These traits MUST match up with the lifestyles, expectations and requirements of the families they hope to share the rest of their lives with.  BEWARE of ANY breeder of ANY breed that makes claims that their dog/breed is the perfect dog for any home or every home needs a "____".
 

PLEASE
Do your research!
No matter if you think a Mastiff is your breed or a Beagle.
Find out what makes that breed tick.  What are the attributes that make it unique.  If you want a jogging partner a Basset is probably not the dog for you.  If you have little time to spend 'working' a dog then a Border Collie won't fit the bill.  If you value a pristine house...a Mastiff is probably not the right dog.