My take on it is no big deal, unless you run into dominance issues. The reason little dogs don't have bad reputations is because when dumb owners don't train them right, all there is to deal with is a small brat. When an dumb owner has a big dog, all there is to deal with is a "monster". What Im getting at is it generally doesn't matter, but if you have a big dog especially a guard dog type breed, you best make clear who is boss. When you invite them up on your bed, couch, and so on it can make it very confusing for the dog who may then assume dominance. If you train your dog well, and he doesn't have an overly dominant personality...no big deal.