It depends on what you want the dog to actually do. Most dogs can be a good watchdog: bark and act threatening when strangers come up to the house. That's enough to deter burglars.

I would take this to the forums and find some bullmastiff owners to chat with- they could tell you whether you are really a good match for them. One thing to consider is that the BM is not really a "hop-to-it" trainable dog. They have a reputation for being slow and stubborn. But once they're "on", that's it! Beware! A "still waters run deep" kind of dog.

The other dogs on your list are generally considered more intelligent and trainable, but will also be "sharper" and more sensitive- it goes along with their eagerness and intelligence.

Be careful for what you wish for... My friend had his house burgled twice, and said, "I'm going to get a KILLER dog!" He bought a German Shepherd/Great Pyrenees mix, and yes, she was killer- she bit him multiple times and was VERY difficult. Had to be put down.

Bruno answered on 12/2/10. Helpful? / 0

Bull mastiffs do not make the best guard dogs. They were bred to take down & *hold poachers, thus they needed to be independent thinkers. They are not the most reliable if you are not home (which is when you really want a guard dog). They can be stubborn & definitely have a mind of their own. The 2 gsds alert bark at sounds & the bullmastiff just looks at them like they've interupted her beauty sleep. Love the bully, but rely on the gsds if someone does break in!

Wiley answered on 12/2/10. Helpful? / 1

I'd say the best guard dog out there is a German Shep Dog. They are highly trainable and extremely smart. They do great with bite work and if its trained right, can be wary of strangers but still a great friendly dog. They def give a good scare to intruders, however you have to make your dominance known to this breed at an early age or your in for trouble.
Make sure you get it from a good breeder that breeds for temperament, not just looks.

Magic answered on 12/2/10. Helpful? / 0

Most Bullmastiffs aren't known for barking their heads off, but every dog is different.Our female Bullmastiff will bark at everythinnnnnnggg.Cat outside,passing car,neighbor walking up the road, knock on the door,etc.I keep the shades up when we're gone(on purpose)and if something moves outside with lightening fast speed she will jump up on the couch, paws on the back, barking wildly while long shoestrings of foamy slobber are slinging all over the window.She looks like a mad dog to all who comes near.Her side kick Kahuna will back her up by standing solidly beside her,hackles,head and tail up periodically giving out a huge "Woooof" along with the famous Bullmastiff 1000 mile stare.Having said that we have an alarm system to protect THEM.Bullmastiffs are massive people protectors,not so much property.Who would be foolish enough to enter after seeing that explosion through the front window tho?They're slow until their *people* are in trouble.They'll subdue by any means,including a bite.

Kahuna answered on 12/3/10. Helpful? / 2

After months of looking at www.homesecuritysystems.net until I finally decided to get a German Shepherd and I couldn't be happier! He's mean when he needs to be, extremely alert and intelligent and he's very good with my children. My youngest son is really rough with him and he just walks away when he's annoyed! Such a great doggie! -Julie

Hitch answered on 3/31/11. Helpful? / 0