For this, i think I rely on body. I mean, the shape, proportions, skin tone is part of body right?
Like, for example, I really love Sakura Miura and Rara Anzai/Utsunomiya Shion, because they have this realistically beauty. Which means, their proportion, is good, Miura's milk white skin, Anzai's boobs shape and texture when jiggling, etc.
I am not a fan of flat chest, like, too flat. Even if their face is cute, i just cant enjoy the sex scenes, nor would watch it few times after. But a small or medium one, would be staying in my folders a bit longer. For example, Remu Suzumori, ooof..big yes. Face is an art, and her body just fit her delicate looking aura. Ai Uehara is a good example too, I mean, she is cute as hell, and she could show you a varying expression from innocent to slutty. She is a beast, man
I love big boobs, but some boobs just not proportionally good for them because they either don't fit well with the torso, too wide, too small or even too perfectly round (implants). Even the face couldnt save it.
On the other hand, some girls have a good body (my kind of proportionally good) and as many times as I see them, i like their face too. The best example is Matsuri Kiritani.
So for me, its body.