BillyBob58, I am a fan of VB. I read a couple of posts about having wet feet with VB socks. This is actually the DESIRED result. The principal of VB is not to stop perspiration or wetness but to contain and reduce both. Without VB, your body will continue to produce insensible perspiration in cold dry conditions as the skin attempts to reach an equilibrium level of humidity to remain at its natural moisture content. With a VB layer close to your skin, that equilibrium is reached sooner as the humidity level is much higher under the VB layers than the outside relative humidity. This has a twofold benefit. First, your body will not lose heat due to evaporative heat loss. Just as the evaporation of perspiration cools you when it's hot, it continues to do so when it's cold. The second benefit is the reduced level of insensitive perspiration results by its very nature in a greater hydration level. The more hydrated you are, the more efficiently your body can generate and regulate temperature. This is true whether it is hot or cold.
There's good reason for the US military cold extreme cold weather boots being VB. During the Korean Conflict, it was discovered that having breathable materials that could absorb perspiration resulted in a much higher incidence of frost bite. The "Mickey Mouse boots" are essentially a thick layer of felt enclosed in rubber. The rubber does not allow the felt to become wet or the tissue in the feet to become dry enough to freeze. These VB boots essentially removed frostbite from the picture, but replaced it with trench foot. The balance was found by using VB boots while removing them and drying the feet several times each day.
My practical experience with VB is that it can offer limited yet tangible benefits above or near freezing and substantial benefits well below freezing. The VB gear I use is clothing rather than space blankets and such. This allows me to put my normal clothing over the VB layers to achieve better results than wearing less clothing and having a VB layer outside of it. The clothing I use are Warmlite socks, Warmlite shirt and non-breathable rain pants. I do wear a thin set of long johns under the rain pants, the other articles of clothing are next to skin. Over those layers I wear my normal fleece pants, a thick pair of wool socks and some form of sweater (when well below freezing).
The results have been my down remaining much dryer while getting a good 10-15 degrees F more warmth than I would normally expect from gear that I had used in similar conditions. This past January, I was able to take a 20 F rated UQ and a 20 F rated TQ down below zero without getting cold. I did bail out on the second night when the temps hit -12 F.
I've also used VB while hiking. I've found that experience to be pretty unmanageable except for socks. Having VB socks on during cold weather hiking keeps my feet much warmer and also prevents my boots from freezing at night as they have not been subjected to the sweat.