None, but I wouldn’t touch them if given to me. For several years we have been dealing with poor results from inverse stack dual layer media. Virtually every day someone comes in and complains about their results with them.
The newer drives with more optimized firmware for this type of disk may make this happen less often. I won’t be one to test this however.
And Memorex is the great whore of brands. They buy anything from anyone, and seem to get poor grade disks even on mids that aren’t necessarily bad. Not that I would describe these DL disks in those terms.
So, my good wishes for you were sincere. My hope is that the tide is turning on this type of disk. My experience helping in this forum over the last few years leads me to question this.