I am a die hard REEF fan!  They are the only brand flip flop I wear!  They are all generally a smaller fit.  But that does not mean order a size up.  It just means that all REEF flip flops fit toe to heel with no excess room.  This makes it usually perfect because all REEF flip flops (unlike other brands) have a bit of arch support and super soft foot bed that kind of conform to your feet.  I live on an island and live in REEF flip flops!  I can and have worn them all day long, and walked miles, all with absolutely no discomfort!!  Great price for a great flip!  Not to mention are super cute on your feet with tons of styles and colors.