Instruct: Classify Amazon reviews into positive or negative sentiment
Query: WORTHLESS

Inexpensive, but worthless. I purchased three 25-disc packages and more than 75% of the discs were defective. When held under bright light, dimples and, in some instances, even scratches, were visible on the recording surface. I replaced these with Panasonic DVD-R discs and the difference in quality is amazing. No more Ridata discs for me.