Variety is the spice of life, but i'll use different positions at different times,
at the start, i penetrate in the missionary style, this is more romantic and is more relaxing for the female. also this allows me to gently enter her a little at a time as to not cause her any pain, although she may be wet, its not always distributed all around inside the vaginal walls. also i happen to be a little wide.
after a while i'll may go into the scissors position or let her get on top, this is less stimulating for me which is a good thing, as it allows me to have more control and last, but this is where most woman are comfortable and get of the most, they can wiggle, grind or whatever to their hearts content, if she makes a lot of moans and sounds when shes coming, that usually makes me go right away also. but i always try and satisfy her first, because once i do, shell be happy to get you off any way you please, i like the doggy or rear vaginal entry or on top with her legs closed, makes her pussy nice and super tight.