excellent for water shoes/hiking
I bought these due to intense blisters caused by sand and rocks rubbing the tops of my feet. They not only did the job but I hiked out with weight in these socks with my water shoes. super comfy. I bought 1 size lower than the chart..PERFECT

Great Wetsocks
I wore these hiking the Subway Trail in Zion National Park (bottom up). This is an 8 mile hike and a third of the hike is in the water. I also used these for another wet canyon called Keyhole. On both occasions, my feet felt great, they were wet after entering the water but comfortable and warm. They do run large though, I am a size 6.5 shoe and I ordered an extra small.

Nice Socks, But Size Down
These are very good neoprene socks, nicely constructed, well fitting, and functional...if you size down. I guess the sizing would depend on how you want these socks to fit. If you wear thick, insulated socks or prefer a loose baggy fit, then the sizing chart recommendation is fine. My wife and I wear these for warm weather stream wading in water shoes or sandals. I have a narrow size 10 1/2 foot and my wife is a narrow size 7 1/2 - 8. Based on reviews we both ordered 1 size down from the recommended manufacturers size, me a medium, her a small. Too big. We use a thin pair of Smartwool hiking socks as a liner under the neoprene and found that the smalls fit me perfectly with just a small amount of foot conforming stretch, (about an inch in length and just enough in width to be snug) which prevents bunching in the shoe. We sent the pair of adult large back and exchanged them for a youth size large which fit my wife perfectly! The exchange policy at Altrec by the way, is outstanding and speedy, so don't worry too much about not getting it right the first time.

Quality Product
Most NRS products I have purchased have fit small. I used these in combination with waterproof boots. I'm really happy with how warm I stayed wearing these socks. I stood in 39 degree water several times and never got cold.

Wetsocks great gift
I purchased the 2mm wetsocks for my son-in-law for Christmas and he loves them! Living in S. CA he has already surfed 4 times with them, wears them around the house and is planning to wear them to a New Year's football game! I don't know of any other gift I could have given him that he could use so many different ways and enjoy so much. Thanks!