John, heated insoles here--I've not had heated socks to compare. My toes and hands get cold easily (poor circulation). When I turn up the power to my heated insoles, the tops of my toes and feet are still cold while the bottom of my feet (and toes) are very hot. More even heat application would seem better, and it seems to me that socks (depending on where the heating wires are placed) would be better as the heated area envelops more of the foot.
On a related note, with dual controllers and more than two heated garments, you'll end up having to choose what garments are joined on the same heated circuit. In my case, my jacket is on one circuit and my gloves and insoles are on the other. My gloves don't heat nearly as well as the insoles, adding to the challenges. I'm better off by far with the heated gear, just mentioning that what you pair with what will affect how comfortable different parts of you are on the ride--try different pairings to figure out what is best for you.
