I have had a trouble finding a nursing/sleep bra that I love, and this is the best one that I have found.  It's cotten which is a huge plus in my book, and the band that goes around your rib cage is covered in fabric instead of just exposed like some of the cheap ones.  Also it holds me in even if I'm laying on my side.  I just don't think it's quite as comfortable as A Pea in the Pod Unlined Nursing Bra, which is not cotten but again very comfortable.  The reason that I didn't stick with the Pod bra is that it stretched out quickly and I now fall out if I lay on my side.  During the day I wear Bravado! Bliss Nursing Soft Cup Bra 32F/G (super highly recommend), and I comfortably wear a medium in this bra; I would think a small would be uncomfortably tight.