I have two sets of these attached to a 2x12 attached to a Workmate. I throw a couple of rubber bands around the brakes and over the tops of the bindings to retain the brakes and clamp them into the vise. The two end clamps are spring loaded to apply pressure to the tips and tails and you can quickly lock them in position. I tune a lot of skis, for myself, my friends, local shop workers, and some of their customers and I have never regretted buying these.
After a few years of extended use, I find a rare pair of cap skis that don't seem to be held securely by the center vise so I added some clamp lassos from Slidewright so that I can wrap the lassos through the brakes to retain the brakes and hold the skis in the center vise.
With a little effort, I could do without the lassos, but I find it quicker with them. Is the difficulty caused by wear on the vice, wax on the vice, my impatience, etc.? I don't know.
For the first few hundred skis in these I never had an issue. At the price you can buy them, I highly suggest it's worth the purchase. Switching between edge angles and side angles is immediate. Rubber bands can retain the bindings so you don't need to try to find and buy or build boot sole replicas to snap into your bindings. I've purchased a lot of tuning gear to make my life easier and I have never regretted these vises.