I bought size 15 and while the size is true to length, the width is just gargantuan.  However, that may be a benefit in disguise.  These slippers are warm.  Very warm.  So warm I need to take them off for a few minutes every hour (I work at home so the dress-code is very casual).  If they weren't so wide and ventilated, I might only be able to wear them half-time.  The outer sole is great - I love the molded rubber for walking out to the mailbox even if it's snowing.  They are a little loud walking on hardwood floors, but worth the tradeoff.  The insole is very comfortable and supportive.  Worn with thick wool socks in the winter, these slippers can't be beat.