I just purchased a size L.  It was hard to determine what size to get.  I am between an 34F and a 34G cup size (before my milk).  The sizing chart made me nervous that it would be too small, but there seems to be plenty of room to grow.  The bra is supportive enough to wear around the house and out in public.  It's not as supportive as your typical underwire, but I was impressed.  The band may be almost big, but I'm hoping that I won't shrink in the rib cage much!!  Overall a great buy.  I'm excited to wear it to the hospital for the big day!!