Same for me. This is the position where I can cum over and over again. I love the face to face contact, the ability to kiss, his access to my breasts, and the way I can completely focus on gripping while he thrusts and grinds. I can also reach my clit if I need to.
Every woman is different, but for me once I start cumming I need him to be deep almost just hold it there so I can just work myself around him, with him just pressing himself hard against my clit.
As far as making missionary better, what makes this the best position, I think, is the intimacy, the closeness, the whole skin on skin full body contact. Eye to eye contact. It's my favourite with someone I care about.