My wife prefers females due to how some males can be about lifting their leg on everything and wanting to mount everything. It's not so much about preferring working females vs. working males. Our first Border Collie was a male. One of my wife's first working dogs was a male; and I've had working males in the past. The sire ended up staying with us for 3-4 weeks and we REALLY like his personality (he was respectful of our other females; no means no as opposed to no means try harder). We do prefer to have only one functioning gender in our pack; it makes pack management much easier (we don't want accidental breedings).
This reminded me of my wife's dog Moss who was able to pee on my leg a couple of times because he lifted his leg before I could correct him. Moss would end up in a crate in our van when one of our females was starting to go out of standing heat because Moss would howl for hours. Our other males were not like this.