in Europe ritek G04's ( metallic purple tops and purple/lilac dye ) was the mutz nutz for ages at 4x writing, they they came out with G05's to match the newly released 8x capable writers .
from that point onwards ritek went tits up with there consistency, i was getting 10+ coasters from 25 packs of G05's .and several panasonic players wouldnt recognise them at all .
i went onto taiyo yuden TYG02 and lose about 1 in 100 from a spindle now . at that time it was very hard to get genuine TY's here .
since then TYG03 have been released, but these seem to be slightly less consistent from posts on here and other places.
my recomendation would be taiyo Yuden 8x -r TYG02 , regardless of if you have a 16x writer .
taiyos seem to be the most compatable diss with more players than any other brand as well ( findings was from a forum that is no longer with us )
the down side is that they are much more dearer than all other brands ( specially in the EU ) , but you are getting reliable media