I admit that there is currently much luck if you want to burn DVDs. You need a good writer and good media.
You might be unlucky and get a burner that causes trouble because something during manufacturing went wrong. But you can also get bad media which causes a bad burn either.

For this reason, I think I will still wait a little with buying a new burner. We had the same problem with CD burners a few years ago and nowadays I can buy the cheapest media along with the chepaest burner and still won't get any coasters.
I guess, this will also be possible with DVD sometimes.

Which firmware did Computer-Bild use when testing this drive? I'm surprised, that they try to make some serious tests now. I guess the discs were checked in the same lab, CT used for their checks.
Usually I would expect some tests about reading speed and that's all and I think you agree with me, that this is not enough to test a DVD burner.