I picked NO PREFERENCE. I have 3 girls, 3 boys.
My boycats are BY FAR more playful, outgoing, people-loving and sociable than my girlcats. Dusty loves people and is defintely playful, but she's sort of diva-style and "snobby" towards the other cats. Jess & K.C. like to hide from the other cats and us humans a majority of the time.
I do believe it all has to do in how they were raised, what type of environment they came from, etc.
However I could never pick a favorite... boy or girl... they all have such neat aspects of their personality & fun things about them, I like 'em both 100%.