Slingbacks are tricky.  the strap can't be too high or too low.  the toe area can't be too shallow or too covered up.

Orly has a great balance.  the heel height is high enough to make pants, skinnies, skirts look good but not too high to be uncomfortable to walk.

the toe area has a slant where the outside is more covered than the inside.  it gives a better support without cutting into the top of the foot.  it also makes the feet look slimmer and cuter.

the strap has a bit of elastic and is low enough to stay on.

i found the mustard yellow one that gives a pop of color to a lot of my outfits.

i believe the shoes run a tiny bit larger because I am between 6 and 6 1/2.  6 in this style fits me well therefore i know that it runs a bit larger.  which is a good thing because one can deal with larger in using a pad.  being too small can't be remedied, just sheer torture.