OK one more time..
Everyone on this boards who knows me well, knows that I re-scan like mad and that I have an ever-growing personal database (683 discs enrolled up to this day) to help me check the stability of the media I use.
I've used hundreds of TDK and Imation-branded MBI PG101R04, and all these appear 100% stable. Consistency was not perfect with the Imation-branded ones, i.e. some discs (< 2%) were defective (very small black spots in the dye ) and produced failed burns, though any successful burn gave me great results both in terms of PIE/PIF scans and real-world use.
BUT... I tried a pack of Ricoh silver edition with this same MID, and these discs were not only very variable in quality from disc to disc, but several of them also showed fast degradation, with doubled PIE values in less than 3 months. Comparable to Ritek G04/G05.
Overall, I consider MBI PG101R04 as a great MID, but it seems that consistency is not guaranteed under all brands, and of course I don't recommend the Ricoh ones.
I don't think that TDK sells R04s anymore, and it's a pity as these were fantastic discs, easily on par with the best of Verbatim and TY. I still have a huge stock of the Imation-branded ones, and despite the (thankfully very scarse) defective discs with the dark spots, they're among my favorite discs.