I think it's funny when people badmouth the Dukes for a touring binding.   I have been skiing on Dukes for three years now, going into my 4th as we speak and I love them.   Sure, they aren't perfect, but they're the best AT binding I'd ever want under my feet.
Hitting the ski hill hard all day in tracked out conditions, no problem.  Doing full day tours in the backcountry, nbd.  I am 6'1", 190lbs, and I have very strong legs, not to mention 190 Bibby's under my feet.
The only other touring set-up I've had was Trekkers, and well, they truly suck to the point that I don't wish them upon my enemies.   When the toe hight thing breaks, yeah, there's going to be release issues, but if you can find a replacement, I haven't experienced any issues with them on the downhill.  Inbounds, slack or back, they are a binding that I fully trust when skiing aggressively.
Of all the skiers I tour with, I'd say 60% of them have Dukes, and there's no real complaints.  The only people bitching are usually older who try to strive for the lightest set up out there and really only ski mellow terrain.
As for comparing them to the Guardian's...   well, I like the idea that we will now have a choice in our AT binding (if you're looking for something beefy like the Duke that is - or else - just get some Dynafit's).    Being able to switch over from uphill to downhill without taking the ski off is something I've always wished the Dukes could do - but how it is done makes me curious because the last thing you need is for your heal to release mid run.     I won't be in the market for a new binding for 2 or 3 years as long as shit doesn't break, so it'll be nice to see how everything goes with the Guardian over the next few years.
I've always been a fan of Salomon bindings, so this is sweet news for me.