I've always used dvd-r for dvd burns. I bought some Memorex R (not - or +)which the clerk insisted worked for burning dvds. When I first started using them, I noticed that maybe one out of five or so wouldn't burn correctly. The Player would eject the disc saying that it was not playable. If I tried putting it in 3 or 4 times, sometimes it would play. I don't know if it's the fault of the discs, the players (I tried playing them on two different machines), or the burner in the computer. Any ideas?