I agree, definitely the individual piggy!
I have had two boys who are very laid back and a little aloof...'you can cuddle me but you'd better make sure you give me the treats first' sort of attitude! Years ago I had a pair of boars who were just adorable, and very affectionate. All were chilled though and never 'scatty' which I think sows can be.
Sows I find tend to be either end of the scale, some very fidgety and low attention span and others who can be incredibly loving, cuddly and generally want the company of humans, even in preference to food. So like others have said, I think its more the individual than then gender...