When I bought these, I read the review about them running small, when I went to write this, I saw the one that they run big. I wear a 7.5 street shoe, and 8 running shoe (sized by a professional) and a 7 snowboard boot (sized by a professional.) I purchased the 39 (w's 8) based on the first review and I too, have a rather wide foot. So which is it? Big or small?? Well, on a Branic device, my foot is just below a 7.5 but my arch length is an 8. For running, I need the 8, for snowboarding (I ride very aggressively) I need the responsiveness of a tight 7.
I think that if I had gone with the 38, it would have been too narrow in the toes. The heel area is super snug and the ratchet is a great feature. My last shoes were a three velcro strap Specialized sz 38 and my foot actually came out on a fall and my shoe was still clipped to my bike!
Too much information? Good luck and even if you buy the wrong size, HuckNRoll is so easy to do exchanges with!