Cornelio, Between only those 2, if u want a more family oriented breed and will be more tolerant of your childs frineds and their parents, id say go with dog argentino, how ever, and i believe jaboa would bak this up, the majority r so nice that a person could steal 1.... Now that not to say that all dogos r like that, thats an unfair generalization, but from what ive heard and seen they can be overly nice.. The presa defiinitly wont be stolen or hurt YOUR children, but they have a very high or hair trigger for aggression, and they would be better if you had more of distance between you and your neighbors. Also, they r not very tolerable of new or strange people, and this includes children as they r people, and problems could arrise. However, i know you didnt mention this breed, but they fall about in between the dogo and the presa, the american bullddog.. I mean a true, old style scott style american bulldog, they like jus about all children, but will not hesitate to engage ANY intruder you might be so unlucky as have come up on you.This breed, i feel has been so commercialized that it is VERY VERY VERY hard to find a good example of the breed, but if you r lucky enuff to find 1, you will have 1 HELLUVA dog!! If you would like to personal message me, i could give you my opinions on the right breeders, and i know that jaboa also has some great ab knowledge and breeder knowledge! I hope that this has helped you.. by the way, i do own 2 american bulldogs who i love to death, but cuz of my already said opinions, i will not own another 1, but i will not tell some1 else to not own 1, and if any1 ele wants to talk about them, just pm me and ill be glad to talk till im blue in the face about them... Mike