Ah, the Marker Duke. The binding that every dumbo who wants to 'get into backcountry' first notices and thinks about.
Based on the Marker Jester, this is simply just an alpine binding that's been slapped on a sliding plate for light use as an AT setup.
Now, simply put, I wouldn't call this a 'backcountry' binding. It's way way too heavy, and far too clunky to use easily while going uphill. It's fine for shorter tours, or sidecountry terrain, and it works GREAT when going downhill, but it's by no means made for long backcountry tours.
However, if you're looking for a solid option to use on your everyday fat skis that you might take out once a month on a short, 1000 ft climb or sidecountry tour where you're using these on more level/moderate ascents, then these are fantastic.
They retain the same great features the Jesters have, of the sideways mounted toepiece spring for fantastic elasticity, sliding metal AFD, and very strong heelpiece chassis, but are mounted on a plate that can release using a central switch - that unfortunately can only be worked when your boot is out of the binding. No quick rips of your skins and locking down the binding to jump down a line with these... you have to remove your boot and change whether they are locked or released - not speedy at all.
But, again, if you're looking for a basic binding that works well for light/moderate ascents while being completely competent when pointing down a line, then by all means, this is a great option!
These are alright, but I trust the Salomon guardian much more. These were great for the first few months I had them, but then they started to wear out. The AFD broke off a few times, resulting in some pretty scary pre release situations. Also, there is not a lot of elasticity, so this also lead to me falling out of my skis due to no fault of my own. There were a few tours on these bindings that felt like the toe piece was about to fall off the ski, but nothing bad ever actually happened with that. This bindings will ski anything, however, and if you can crank the dins, this is a useable binding for sure, but there are better options.