Obviously these guys have done a lot of work over many years to refine this product. It works really well but takes practice and skill. I suspect the creators are now so good at using these systems they may have forgotten how tricky it can be to get used to holding a thin, flexible blade in place purely by hand, not with the dominant hand, etc. it’s tricky and takes practice. Don’t expect this to be a quick and easy way of getting sharp knives.
My biggest issue was the construction and quality relative to the price. We here in Canada get horribly gouged on price so obviously I ended up paying quite a lot more than those south of the border, but even taking this into account I think this costs WAY too much for what it is. I paid over $300 for this and it’s basically a piece of plastic with some rods attached and a few stones. For that much money I would expect it to be machined aluminum rather than injection moulded plastic from China.
Overall I wouldn’t recommend this product at this price.