from what I've seen an American bulldog of the right breeding , right owner , right raising , can make any "working" dog look inferior , at anything ……..there been some great protection dogs , catchdogs , sport dogs , pull dogs , smart dogs , love to bite , lots of fight , plenty linebred on game ……. Banuelos , boyd , Metcalf , litchardt , lopez , mullens , bbk , leclerc , nor cal , koura , JDJ too many to remember , long pedigrees of proven dogs bred and raised by proven working dog folks , some of those dogs were unsuitable as anything but workers …….. there are some pretty adept trainers , I've seen some pretty crappy "titled" dogs …… outside traditional working breeds in the united states I've not seen the kind of breeders I've seen breeding AB's breeding any mastiff breeds , possibly a couple bandog breeders/trainers …..