in my experience males are more friendly and confident, and my females were a little skittish and harder to handle, but they loved cuddles like the males...they do change a bit when theyre pregnant, but then again, most creatures do
You can get real characters, dominant as well as laid back piggies in both sexes. Some boys can be ever so laid back! Older piggies are often mellower than hyper youngsters, but both have their own charm.
Generally, what you put into your pets, you will get out of them. I find it more important to go to a rescue and meet and handle the piggies - gender and looks can be less important than you think when you come across that engaging bundle of fur that steals your heart. Often, the less showy piggies have the big personalities, but you won't know that unless you meet them with an open mind. Several times I have come back home with a different piggy than the one I'd initially reserved!