I'd say they are fairly close in durability, with similar builds, mounting patterns, and steel forks. They do have somewhat different release mechanics and if that's a concern for you, plugging your info into the release calculator would help for a recommendation.
Hi Mike, yeah Dynafit discontinued that binding and the brakes are hard to come by. The Radical brakes aren't designed to be swapped with Vertical brakes. That said, they are the same basic design and there are a few ways to hack the system. See here for some more info.
Hi Peter, the toe plates are priced individually in case you need one as a replacement. The Vertical ST toe plates are ~6.5mm thick under the cast metal vs ~1.5mm for the Speed Turn / Classic. The mechanical part of those bindings are identical so you can swap plates to reduce your pin height delta by 5mm. Dynafit does not have the anti-twist device available at this time and it's unclear whether it will be offered this season. We are currently recommending the Maruelli solution while that is being sort...
Hi Wayne, yes, the SCTT features both lateral and vertical release mechanisms similar to other tech bindings. The vertical release works by allowing heel pins to be forced apart, letting your boot slide through. The heel tower spins in both directions for a twisting release at the heel, though like most tech bindings is not certified to DIN standards (which were written with lateral toe release in mind). This has some interesting (positive) implications on your knees compared to certified alpine bindings...
Hi Steve, the Seraks is more of a wind shell, using the Gore Windstopper membrane. The Mercury uses a proprietary fabric blend and is a bit warmer with a very light fleece lining. It also has the cool back-of-the-arm zip vents.