Not sure how good this is, my knife seems considerably sharper than it was before using this but maybe my expectations are too high because I feel it could be better. I only sharpened it for about 4 minutes straight though. I might edit this later.
If you're looking for a good, cheap, and efficient way to sharpen your knife, this sharpener is a good way to go. If you're not great at sharpening with whetstones or you don't have access to the right machines, you'll definitely be able to use this. Good grip, easy to handle and use. Only downside is if you use it and aren't super careful your blade to slip and knick you. Overall 9/10