I purchased two pair of Stephenson's Warmlite vapor…
Materials: fuzzy waterproof nylon
Use: very cold weather hiking
Break-in Period: none
Price Paid: $9
I purchased two pair of Stephenson's Warmlite vapor barrier socks for a winter mountaineering trip. They are very inexpensive, two pair cost less than the next most inexpensive vbl sock.
The material has, so far, been durable, and the stitching has held up well. Much more durable than a plastic bag. Also, the material is not a typical laminate; it is softer and easier to wear than normal coated nylon.
Seams are a significant issue for vapor barrier socks, which take a great deal of abuse. These socks have worked very well and are custom-sized to your feet by Stephenson.
One essential, vital point - Stephenson sent these socks without sealed seams. I think they will seal the seams upon request for an additional fee. Without sealing the seams, these socks may not only be useless but dangerous. Any ordinary tent seam sealer will work - I used the brand Stephenson recommended.
Usage tips - wear a thin wicking sock inside the vapor barrier, it will make the experience more comfortable. Also, take the vapor barrier and wicking sock off and wear a new pair, or just a dry outer sock. Prolonged use of vapor barriers without changing socks can cause trench foot, a painful, trip-wrecking and potentially dangerous condition. Make sure you test them with the sock combination you expect to use - you need to make sure that the added layer doesn't constrict your circulation, which will ensure cold feet.
Finally, these are best used in very cold weather. Very cold, meaning I won't use them on a hike where the temperature is over 15 degrees fahrenheit.