An insert should hold the screw in better, but its just like anything mechanical - the more pieces, the more things that can go wrong. Swapping bindings between sets isnt something best done at the mountain, its best the day after skiing in your garage without snow and ice everywhere.
After installing and summing the experiences of a few friends who ride these - great for some people and certain situations. Pretty much write this option off if you ever plan to sell your skis however, or hope to find someone with your exact BSL and needs that same binding setup. Cost is sorta pricey still as well. If you want to keep your skis for the rest of your life and can afford it, go for it! Makes the most sense to me at least to have two pairs of skis and two sets of bindings (one AT/tour obviously), or do one pair with an alpine/tele mount for the rare multi-skilled skier.
Go to the thread on TGR entitled "The Swiss Cheese Experiment" -
"He was the spearhead of the mod force. Everyone knew who he was and feared his wrath. There really isn't anyone like that anymore. Rowen didn't just delete their threads, he deleted their souls."