I use 100's of cd-r's for my business every month. I have used practically every brand available without too many problems at all and I can honestly say that these are the worst discs I have ever bought which is surprising coming from a brand like Memorex. I have used about 70 of the 100 and so far about 15 have ended up in the bin which is an alarming failure rate. Also, the discs often seem to stall the burning process and it can end up taking 10 or 15 minutes to burn at 40x speed or they just crash your burner completely! Vey poor quality - would never buy these again. NOT RECOMMENDED!