Guys, I have a pair of the 40 Below TR Overboots. Weight is 14.4 oz for a size 11 (L) to fit my hardrocks. They are custom built, so I had to wait a couple of months for them. They are quite a beautiful piece of gear, but I would not recommend using them in temps above freezing (like mentioned in the article) as I believe these perform much better in cold climates.
I use a vapor barrier sock, thin sock, Montrail Hardrock, and then the Overboot. The logic is to create a system which moisture cannot enter, either from the outside elements or from the foot. This would, theoretically, always keep you feet dry...and dry feet are warm. :)
Only a few day hikes so far with great performance, but I'm heading out this weekend with them so it will give me a much better idea of how they perform.
I should mention that these cannot be used without a snowshoe or crampon as the sole is not durable enough to handle abrasive ice, ground, or rocks.