I prefer someone my size and skill level over gender. I'm 5'2 and 115 lbs (probably 20-25%BF), so it's rare to find someone my size of either gender at my gym.
I'm about to make a huge generalization, but one of the biggest differences I've noticed between men/women at my gym at the beginner-intermediate level is that women focus a lot of technique but are afraid of their power with new partners, and men are so focused on power over technique. For both genders though, when people start becoming more comfortable with their partners/gym environment, they tend to even it out.
For that reason, I *hate* working with guys who are new to the gym and still trying to prove themselves with power and don't have good technique (and can't seem to implement it after being given instructions... they just hit harder with the same poor technique ugh). I don't mind working with new girls though because they're generally much more open to receiving help or making adjustments. I *love* working with men and women below 5'6 who have been at my gym for >2 months. I will say, there are about the same amount of men below 5'6 as women just because there's way more guys in general, but they're mostly all great and put forth effort (there's a few specific people I still don't like working with for various reasons- too young/small/frail, too aggressive despite being past the typical 2+ month benchmark, too mopey/ doesn't want to be there).
My least favorite thing about working with guys is when they wear long, baggy shorts because it makes it really hard to tell wear their leg is (and most importantly the crotch) for leg kicks. I've come very close to kicking some guys in the nuts because of these stupid, long, baggy shorts.