This is a pretty intricate question and my answer is based on what I have read and personal experience. If I understand correctly, knives with dimples or scallops are supposed to create more air space between the knife and the food, thus reducing adhesion and making release of the food easier. This seems to be the reason most stated for an advantage of this kind of knife.
The deeper or larger the scallops are, the more effectively the knife is supposed to work, as there is less contact with food. I find that slicing motions across the food are more effective than straight cuts down to the board. (However, I find this to be true with any knife when slicing foods that adhere to the blade.)
As you stated, even though you have upgraded and added knives to your collection, you usually reach for your Wusthof. We have knives of all types, from fairly cheap to pretty expensive. We do the same thing -- reach for those trusty favorites.
I find that as long as a knife is kept sharp and it feels good in your hand, it doesn't really matter otherwise. And back to your original question, we have several knives with scallops or the granton edge, with those being some of the more expensive knives we own. As far as performance, I don't think we've yet seen any advantage to them. (Sometimes on the first slice or two the food releases more easily, but after that I can't really tell any difference.)
I don't know if this qualifies for an ideal answer and I'm sure that there are many others with more knowledge of the science behind this. But, I do think that as long as you are using an appropriate type of knife for your task and it feels good in your hand, you can't go wrong.