OK, here goes.
First, I'm biased. I injured my knee (ligaments) and ankle (cartilege) in a simple accident on piste with a Fritshi Vipec. The release was sticky/grabby/catchy, and the injury occured before the binding released. So I don't consider the Vipec/Tecton safe at all. On the contrary, I think it's deceptively unsafe, because people believe that it confers some saftey advantage and ski it normally, when, in fact, the release is unpredictable and inconsistent.
Second, I consider all pin bindings very risky for people who want to avoid leg injuries. That's the starting point. These bindings should not be used at the resort, and when skiing with pin bindings, one should ski with a great measure of caution and care. Don't take my word for it; listen to all the conversations out there, including from one pro skier on Blister who said, "Those bindings [pin bindings] are f***ing dangerous!"
OK, with that out of the way, I think it's important to acknowledge that "safety" means different things to different people.
For some people, it means absolutely not releasing, in any situation, for example, locking the toe above consequential terrain.
For other people, safety might mean good power transmission, elasticity, and solid ski feel, like folks using the CAST system with true alpine bindings, even ski tours with huge vertical gain in the Himalaya.
For others, safety means light gear that they can carry through long traverses, over big objectives, and so on.
Those examples represent the extremes. The rest of us are left to figure out what safety means to us, in a complicated, crowded field, with lots of competing (miss)information. There is some limited research and data out there, but it is not widely known (see below).
For my part, I really don't want to injure my knee ligaments, so I look at binding safety through that lens. Here is where my reasoning has taken me.
A binding that releases laterally at the heel, like classic tech bindings, does a better job of protecting knee ligaments, compared to bindings that only release laterally at the toe. This is the reasoning behind the Knee Binding and the new Protector binding, but it's also an coincidental advantage of classic pin bindings. So, at first, I gravitated toward classic tech bindings.
Then I realized that the truly dangerous thing about tech bindings is the metal-on-metal interface with small surface area. The release function with pin bindings is unpredictable at best: add in some snow, ice, dirt, wear, forces pushing down and sideways...and it's really a gamble that a pin binding will release when needed.
For this reason, I think that the Shift provides the best knee ligament protection of all the touring bindings out there. True, it laterally releases at the toe (so theoretically it would not be as safe as classic pin bindings) but the plastic-on-plastic interface with large surface area is far more predictable and tolerant of real world use compared to pin bindings.
Yes, the Shift is heavy, but for my tours, weight is not an issue. And if you keep the Shift adjusted, it works really well, including on piste, so you can safely ski/train with a touring set up. This is a huge safety factor! I find it crazy that so many people rarely ski on their touring gear, and then go out touring, where they will likely encounter some of the most difficult conditions of the season, on skis/boots/bindings that they haven't spend much time on relative to their standard alpine gear, probably carrying a heavy pack with tired legs, and just expect/hope/dream that they will ski competently. What a dangerous situation! Just saying.
What if I absolutely had to choose a pin binding? I would choose the Dynafit Rotation (again, see below). Yes, that's a heavy binding, but I would loose a little weight compared Shift, and I would also loose some weight going from a Gripwalk boot (for the Shift) to a non-Gripwalk boot (for the Rotation). I like the look of the new Scarpa boot coming out next year, with a Gripwalk sole integrated into the sole; it should save some weight compared to existing Gripwalk boots.
Anyway, what's the research and data I keep talking about? In a word, Skialper. Any true ski touring geek should get together the Euros, brush up on their Italian, or download a text translation app for their phone, and order a print edition of the Skialper buyer's guide. It is the best resource about touring skis, bindings, and boots in the world. No comparison.
For two years in a row, Skialper has tested multiple pin bindings for release function, using a variety of tech inserts (Dynafit, Atomic/Salomon, others). The only pin binding that consistently falls into the "green" zone of release, meaning that is releases smoothly at the determined value, with inserts from all manufacturers, is the Dynafit Rotation. There are two components to this: first, that it's the only binding that consistently falls into the green zone, and second, that it does so with a range of tech fittings. That tells me is that the extra rotation feature at the toe helps the binding overcome the natural tendency for pin bindings to bite and grab, and helps the pins ride out of the toe sockets, in a way that is different from all other pin bindings. It also tells me that this binding tolerates of changes in dimensions, specifications, angles, pressures, and so on, which will translate into safer performance in real world conditions.
So that's my ranking of the "safest" touring bindings:
1-Shift
2-Dynafit rotation
3-Classic pin bindings
4-Fritschi Vipec/Tecton