I have been using my 7/5 Henderson hyperstretch for several months now for over 20 dives. All my diving so far has been in Lake George, NY, except a weekend down at Dutch Springs in PA, pretty cold all around. I did buy a 3mm core warmer to go over top of the suit as the weather got colder and the water temp started to drop. The lowest water temp I have hit so far is in the lo-mid 40's and I think that is pretty darn cold. I have been totally warm with the exception of the exposed part of my face and my hands. I like the Hyperstretch so much I got 3mm gloves and have been using them, so easy on and off. but now that my hands got cold I bought the Hyperstretch 5mm gloves, still easy on & off but less dexterity but at least my hands will be warm! Temps continue to drop however so now I have added a 7mm Henderson Hyperstretch core warmer to my dive bag but I have not used it yet. I first bought the 3mm as I did not think a heavier one would fit over me and the full suit but it did and easily. I gotta admit, I love this hyperstretch stuff! For the person asking about the gold core with hyperstretch, I think it will lose some of the ability to stretch with the bonding of another material to it as that material will not have the same stretch properties. the only other drawback so far is when you come out of the water on a chilly day, the wind goes right thru it.