The NEC is not extremely picky and should write very well on most media.
Faint stripes or shade-rings are normal and can be seen on disc regions where the drive has burned at different speeds.
For example, if you're burning a disc and select 8X write speed:
It will start burning at 4X which will be one color,
then burn at 6X which will be a slightly different shade,
and then finish at 8X, which will be yet again a slightly different shade.
So if you burn the whole disc at 2X, of course you won't see any color differences throughout the bottom of the disc
Burn one of your Taiyo Yuden discs at 8X.
It should turn out perfect and play in all your drives.