I just asked my uncle about this, who now has a tropical tank just under 500 litres devoted to livebearers of all types and genders, except swordtails. So, this is what he said:
Mollies:
Male- More sort of out-there, a bit more active, see more of them, fly around the tank occasionally.
Female- The more laid back of the genders, just chills out a bit more.
Platys:
Male- Irritating to females I have found, the same with my uncle. Just constantly chase them around. Fights with other males sometimes aswell, more aggressive if provoked it will go for it.
Female- Just seems to look at the males like "the hell you doin"? Far more laid back.
Guppys:
Male and female- Tend to stay at the top of the tank more than the others, die off easier, less aggressive, more prone to diseases and bullying.
And he hasn't ever had swordtails and neither have I.
Hope this helped.