I'll bet that a lot of these RMAs are due to bad CD-DVD Quality Score scans
I'll also bet that a lot of excellent burners are being returned because most people don't have a reliable reader.
All of my burners are capable of burning at the same quality, but one out of the three absolutely SUCKS for scanning. I probably threw out 50 discs because my shitty scanner had problems FTR, it burns incredibly well with WOPC turned off. Even on this incredible disc, it gave me pretty bad PIE. On lesser discs, it claims they have POF.
Here are scans of the same disc on three different burners: