I usually wear 8.5 4e. Went size up to 9 in width. First time great. Be careful, leather scratches very easily. In addition, since the outsole is made of rubber compound, you may notice tiny creases in the heel from walking after wearing it. No one will ever notice unless they're very clear, but I thought I'd mention it just in case there's some kind of compulsive client involved. As for the vents, I didn't notice a huge difference in cooling my feet, again I'm lucky my feet don't get too sweaty.