Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Not as good as a professional sharpening or by hand but...

Even though I normally use a diamond sharpening block and know how to check the angles of the bevel, I have to admit, this device is quick and easy.It gives an acceptable edge as long as you use it according to directions. It is convenient, as it can sit on your counter or be pulled out of the cupboard in a jiffy. So you tend to keep your knives sharp. The problem with hand sharpening is that it is finicky work that takes time. This is faster and easier, so you tend to do it oftener.A sharp knife is actually a safer knife as it cuts easily. If you force a dull knife, it can slip and make a nasty cut. (The worst cut I ever saw was with a knife too dull to cut wax. It had no edge, but made a nasty, torn gash. The user was forcing the dull edge through wax and got injured.) So keep your knives sharp and in a block and use them with respect. This sharpener will certainly help you do that.