Heh, I have had various DVD burners (powerbook g4, 2 mac minis, probably at least 5 IDE/PATA and 1 SATA) and I don't think I tried Memorex in all of them, but certainly at least 3 and had a failure rate much higher than with Sony. I used to burn literally hundreds of DVDs and with Sony 8x and 16x (later when 16x became available) DVD-R with a failure rate of about 1%.
Of course I could have just got a bad spindle or 2 of Memorex.