I live in Tenerife. Presas are not uncommon here. The Canaries are not named for the birds. The name comes from Cana - dogs. Presas originate here.
My neighbour has one and her daughter still has the litter-sister. You could not wish for a better neighbour dog than Elfa. When she happens to come round to my house to say hello, the worst thing she does is pick up my favourite leather/chain flip flop and carry it around in her mouth.
She is an absolute sweetheart as is her sister (yes, the one who had the oops litter for anyone who remembers that thread). In fact, I have yet to meet an aggressive or bad to the bone presa and I have lived here for six years.
Amstaffer, if you want some links to websites to breeders of the original presas, I'll PM them to you.