I'm 5'10, 140lbs and I purchased a 9.5. I wear anywhere from 9-10.5 depending on the shoe. The 9.5 is the right length except it is narrow on the feet. I circumvented this issue by changing the lacing, lacing up the side until the top two eyelets on the left foot, and the top eyelet on the right foot (unsure if it's my feet or uneven manufacturing). Here's the downside: accommodating wide feet opens up the webbing on the tongue. I took the boots through a small stream crossing and once the water reached the bottom of the tongue, water got in the shoe.
No problems with the shoe construction or waterproofing otherwise, just a problem with my wide feet. They feel great going up and down hill. If I sized up I'm sure my feet would slide going downhill. My feet were starting to hurt around 5 miles into the hike so we cut it off shortly after that. These shoes likely need some breaking in. I wore them with the darn tough 1/4 hiker socks.