Basically frame bindings a la Baron, Duke, F10/12, Guardian etc are for people with regular DIN soles that normally ski at resorts that want to also tour. They are good for entry level tours and for the occasional sidecountry trip, but the pivot point, weight and stride is less than ideal. They *can* work with *some* rockered vibram soles but it effects the release characteristics in an ambiguously negative way so it can be kind of rolling the dice if you do it. It is also a more laborious hike in frame bindings since when you lift your heel you're bringing the whole binding frame along for the stride. They are also typically more damp and can give the "dead underfoot" feeling since you're not feeling the ski flex while you're in the frame. These may be a good entry point, but if you get really into it you'll probably be looking to upgrade to full on touring boots and tech bindings eventually.
Low Tech bindings a la Dynafit, etc. utilize toe pins and heel pins to secure the boot. Soles don't mean shit as they aren't part of the binding/boot interface so you can have fully rockered soles and vibram without a problem. The stride is fantastic since it puts the hinge point right at your toe- as would a natural barefoot stride- which is a far more intuitive motion than any frame binding. Also during a stride you're only moving your boot and not the binding at all so it's much MUCH less exhaustive. Weight is also FFAR less on low tech bindings. They are not however for everything- it's a non elastic metal-on-metal connection from the binding to the boot so you feel EVERYTHING. This means nothing in pow but if you were to ski them on hardpack prepare for your fillings to rattle out and most likely your bindings to eventually break. Release values are also sketchy at best and do not conform to any standard. Also big spins and landings can result in prerelease and any amount of ice in the binding or toe pieces can fuck you over in a hurry. They are simple but they do require specific attention to minutia to operate properly.
In short, frame bindings are for the occasional tourer who has alpine boots and wants DIN release and tech bindings are for those who are REALLY into touring and want to go farther faster and don't give a shit about a binding's hard snow performance shortcomings as they're only touring to pow.
That's obviously skipping a shitload of stuff and in-between setups that are emerging nowadays, but that's the basic gist.
