It depends on the dogs job. Buddy or weapon?
I used to think male dogs were better. Bigger and smarter and all that... Now I'm not so sure.
My Norwooding neighbor always had female dogs. He never said - or knew - why. I asked him and he didn't know. I figured more "food area loyal."
Anyway, i have my first female dog and she's slightly smarter than my male dogs were. And just as scary to visitors.
So far my bitch dog is more controllable via food and "harsh tones" that my male dogs were. So that's a plus with larger dogs.
As far as any pet dog goes, you should have it spayed or neutered if you want it to stick around instead of looking for sex. But it depends on the dogs working environment. It's cheaper for them to breed than for you to buy them.