[stoppingdown]

I bought the Peak Design to try it. My evaluation so far: its biggest advantage is that you can lock / unlock it easily using a single hand (two fingers, to be precise), while the Op / Tech requires more strength and - at least in my case - two hands. This is really annoying while you're trying to move gear back and forth from the bag, attaching and detaching it.
Furthermore the strap is smaller so you can keep it at the wrist for a whole photo session, without e.g. the need to remove it when you drive. Honestly it isn't impossible to do the same with the Op / Tech if you wear an attire with long sleeves, but e.g. it requires more time to fit. The Peak Design also has got a magnet that can be used to keep the wrap in place even without long sleeves.
On the other hand, if you don't plan to use the thing only as an emergency tethering, but also to keep a camera hanging for some minutes, those good features fire back since the wrap tightens around the wrist up to the point of hurting you (also because it's thin and not as comfortable as neoprene). Perhaps wearing a gym wrist wrap under the thing could solve the problem.