***TL/DR Synopsis***
I have one, it doesn't bounce much compared to older ones, but I'm moving away from having a strap on my Hasselblad cameras for normal shooting. I do like them and would choose them over most other straps because of the neoprene and quality.
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I have an Op/Tech Pro strap on my 501C at the moment, but I am more inclined to not use a strap because the right clip does get in the way of winding at times, and if you have a prisim on the camera (instead of the folding WL finder) the camera is going to likely want to flop in an akward manner (unless you are using a very long lens). If you are shooting out of a bag or satchel, I think having the straps on are more hassle as well.
But let me answer the original question about the straps with a little history... the very first Op/Tech straps came out in the mid-80's I think? At least that was when they first made their way to US camera stores. I was working at a store at that time and they had the Pro and another model similar to the Classic today. I don't recall if they made hand straps, etc. back then, but I did have a tripod strap from them in the late 80's.
Back then, the neoprene was very similar to the material used on scuba diving suits. It was quite pliable and springy and it would cause the camera to bounce, especially if it was a heavy camera, with a MD, larger lens, etc. Bounce, bounce, bounce. But, it did take the shock off the sholder a lot, so that aspect was good.
It was also great for placing between the camera and a rock for a little cushioned spot to shoot because the wider Pro strap was 2" or so wide.
Lastly, it had plastic connector QR buckles on each side of the strap so you could remove most of the strap and just have a hand-carry strap (not a hand-synch, but just a really short strap that you could use to pick up the camera by connecting together the two strap segments that connect to the camera).
They've changed the straps since then. The neoprene is much, much stiffer. It is stiff enough that I don't think it bounces much at all. A little bounce is what relieves your shoulder of some of the strain of carrying a camera for a long time, so eliminating it completely probably wouldn't have been a good thing. They moved the strap coupling QR buckles out from near the camera to the end of the narrow nylon strap (at the point of connection to the neoprene portion). I don't know why they did that, but it defeats part of the point of having the QR buckles, which is to remove as much of the strap as possible to get it out of the way.
I used to love the Op/Tech straps when I shot 35mm a lot. They seemed to suit the cameras well and I used them through my college years shooting a lot of PJ for the newspaper on campus and the yearbook as well. My impression of the current Op/Tech Pro strap on a Hasselblad is that I don't love it, but it is a good strap. I think as I'm learning the Hasselblad cameras more, it's pretty clear to me that they do function better without a strap so I'm going to probably go that route, but maybe think about a hand strap (for the left hand) for security. Free up the right hand and side for the film winding.
This may be a bit of a learning process for me, because on 35mm-style cameras (including modern digital Fujifilm GFX and X cameras), I use my left hand to operate the lens (focus, aperture) and my right hand to do the rest, but if I have the hand strap on my left hand, I can't really use it to do the lens settings, except maybe focus. All the rest will be with my right hand while I keep hold of the camera with my left. I guess that's what the camera forces me into anyway? I'll have to pay closer attention as I use it.
I do like to walk/hike with a camera in my hand, and maybe at those times, putting a full strap on would be beneficial, so if I'm not traveling light, I will bring the straps I have (an Op/Tech for the 501C and a Hasselblad nylon strap for the SWC/M).
