Marker saw a niche several years ago in the segment of the ski industry that wanted the option of touring, without the hassle of buying a whole new touring setup. To their credit the Duke mostly satisfies this need. If you’ve been living in a box for the last five years the Duke is a high din, more torsionally rigid binding that has a touring mode. Thus, for those that only tour occasionally it’s perfect. The high din and strength of the binding lets people ski confidently in the resort, and the touring mode enables occasional slack-country mission.
However, before you drop in on a pair of Dukes there are a few things you should know. First, they’re heavy- which makes sense. A durable, high-din binding should be a bit bulkier. However, if you’re going on long tours it can be a bit more strenuous. Second, to click the binding into tour mode you have to take your boot out of your binding. This, when combined with exposure, can be a bit sketchy. Third, the touring system tends to build up ice, making it difficult, sometimes extremely difficult, to put the binding back into ski mode. Lastly, the rise on the binding is fairly large, making your actual stance on the skis different- which is a concern if your a really discerning skier.
I’d say if you spend a significant portion of your days touring (over 1/3) I’d look into a lighter setup provided by other companies. However, if you’re just looking for a bindings that will provide you with the ability to go on the occasional tour, I’d go with the Duke.