I recently got the black/white version of this bib.
I spent a long time deciding whether to get medium or small.
First of all, this is a very comfortable bib. I machine wash cold and the bib is just fine.
I was very luck to have chosen medium. I rarely saw a review with a person my size, and it was hard to gauge. I hope that this will help out some of the smaller people.
Height: 5' 7.5'
Weight: 130 lbs
Good luck on picking the right size :)