Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Don't buy this one!

My daughter purchased one of these for me. I have had three different sharpeners of this type, but this one was the worst by far. At first, it did a great job, but after about ten sharpenings almost all the diamond dust is worn off. I have gone back to an Eze-Lap 8" round sharpener that I have had for about five years. Much of the dust is worn off this sharpener also, but only after hundreds of knives being sharpened. I will but another of these and never switch again.