I have had quite a few of the dogs you asked about, sometimes with a rescued/foster small dog. My rottie would tolerate anything (except food sharing) with anything SMALLER than him. Sad they get such a bad rap from insuransce co. This may sound crazy but I had a 20lb male poodle for 15 years that challenged every dog I ever brought home..he had to be put in his place NOT the big dog by ME from jump. Find a dog breed you love..and DO NOT be afraid of a cross a Boxweiler is a helluva dog..I had a lab/pit that lived with above poodle for 14 years That may have been the best all around dog I'll ever own. I think that MD like NJ is very hot and humid so I agree a short hair dog with a snout would be best. Look at dogs parents and the home they come from ...only way I buy dogs...I find breeders for profit BS artists who will say anything to justify their crazy prices. My 2¢ I have had no problems with the following dogs living under my roof with a small unfixed male 20 lb poodle..who though he was a 150lb CO A Johnson am bulldog..(gus on saving grace) big mean looking little drool,not a big shedder..DO NOT GET Scott bloodlines, Painter, Leclerc, Hines, as they have 2 much prey drive Boxer, again not a show breeder I have a family who spent 1500.00 for a show dog who has stomach issues..but I have 2 friends that have homeraised dogs a bit to large for show standards that are 100% Boxweiler, neat dogs big scary yet smart enough (the rottie) to be really sharp. Bullmastiff from working stock..again check parents Dobie smart scary looking and VERY trainable neocorso ..so hard to find but the 2 I rescued made me buy my current cc whose parents lived with pugs. My pups new best buddy is a neighbors 7lb chi wa wa CC for above reasons And no matter what dog u get even another "foo foo" type your current dog will be jealous and you'll have to work thru that( just because you'll HAVE 2 spend so much of your time with puppie) last thing big dogs need to be MULTI dog socialized and multi people socialized ( if u want him 2 go to work etc) Let me make it clear when I say big and scary looking I do not intend that for the people on this forum I mean it for the people who know very little about our type of dogs.