Johnny - the liner socks are designed to pull moisture away from your feet, my heavier Simms socks also do this of course. If i wear just the Simms socks my feet will get cold over time and they take alot longer to warm up, with the liner socks they warm up quickly. My feet only get cold when im standing in the river swinging flies, if im gear fishing im hardly ever in the water.
liner socks i have are from Wholesale sports and are the ones made with CoolMax. exactly they same as the Simms liner socks but less money. I only wear these during the winter months steelheading otherwise its just the Simms or even lighter socks
Save yourself the headache and buy quality stuff the first time, it will save you money over time and you will enjoy yourself more when your in the elements