Good but expensive, some limitations
I've managed to get some knives razor sharp with this, to the point they'll easily slice cleanly through paper and shave hair. However, don't expect it to work miracles. I tried to sharpen some dull kitchen knives and the results were poor. I think the supplied rods are good for knives that are in reasonable condition to begin with. There are some more abrasive diamond rods available at significant extra cost. It probably could sharpen those kitchen knives with a lot more effort and time, but the whole point of set like this is that it saves you effort and time. Nearly £60 for a plastic box with four ceramic rods is expensive, and it should really cope with all levels of required sharpening at that price. An additional set of more abrasive rods for initial shaping of very dull knives should be included as standard.