My experience with DVD-R using a Memorex 530L burner with Imgburn at 2x to use in Gamma 0.3 each tested with 3 titles & same iso: Mario Galaxy, Zelda Twilight, No more Heroes.
-Memorex DVD-R: Wii makes loud noises and can't even start the discs. Errors even on the channel screen.
-Verbatims DVD-R from taiwan: All games work but they launch slowly, sometimes giving error but I eject and reinsert and they launch fine afterward. Less loud noises, but the videos are very sluggish and end up crashing the Wii except in No more heroes. The video quality is like original.
-Fujifilm DVD-R: I underestimated them...Load fast, no noises, no errors, no sluggish videos . The only problem is minor sluggish audio in some charged video scenes like the attack of Bowser in Galaxy and the video quality is less than the Verbatims & originals. (strange?)
Maby I'm insane but I really saw a difference in video quality between both and I think this is why it worked so well as if the videos are less heavy to load.