They are very different in the looks department.
Niko has a younger look, Chinese-Korean, with beautiful naturals and curves but probably a little baby fat. Face is average cute but with some pocks.
Yoyo, is more mature great natural physique but not as big up top. Not as supple.
It is a matter of taste I think, check reviews of each.
Again, when in doubt try it out. A mix of sure things and TOFTT's is what makes the hobby fun. No?