there is a site specifically for mastiffs. It's mastiff web dot com. They will answer all of your questions and point you in the right direction. And,to answer your question-Yes,they do drool all over the place if you let them. By that,I mean,you have to keep cloths/rags handy and make sure to wipe their mouths after they drink water,etc. I have heard a few say theirs don't really drool much though. It's best to speak with as many owners of the breed as you can. Mastiffs are a great addition to most families,but aren't the perfect ones for others. Good luck!
In response to your question regarding mastiffs, I really can't answer the question in total honesty. All dogues aren't going to drool the way it was portrayed in the movie. That dogue was given something in his mouth to make it look worse than it actually is.
My first dogue drooled like a faucet, I think it was because he didn't have a correct bite. The one I have now came from an excellent breeder in upstate NY, he doesn't drool at all.
My next thing is to do alot of research into breeders and visit them to see the parents of the puppies. They also need alot of socialization and someone who is going to show them who the alpha is. My dogue doesn't care if you stick your hands in his food while he is eating, and lets you take anything out of his mouth.
They are an asset to the right people and are not meant to be thrown in the backyard and forgotten (no dog is). They love their families and want to be with them all the time.
So, in general they aren't for everyone, can and will take advantage of weak people and even with socialization they are wary of strangers. Mine likes only the people that he knows from puppyhood and doesn't care to meet new people.
I suggest you go to www.ddbs.org for any other info you may need and to look up breeders in your state.
Have you ever heard of the Gentle Giants in Norco, CA. They say that Mastiff do not drool but they do get bucket mouth. That when they drink the chin gets wet and that is what drips. I can't remember if they have any information on the website but it might help.