yuki chan: That is really quite scary! Ritek's quality control (or lack thereof) really is terrible. I would definately complain to Memorex... I've heard they quite good about replacements.
As far as TY bonding quality goes, it certainly varies greatly. I wouldn't try to determine whether TY bonding is getting better or worse without taking a large sample of discs from as many sources as possible...
Also slight OT, I rescanned a few of my year old Fuji branded RICOHJPNR01 to find that some of them are failing at the edge. Considering I ALSO had some Sony branded RICOHJPNR01 fail on me, I have completely ruled out using anything made by Ritek for anything resembling important data. It makes me that much more skeptical of Maxell's recent deal with Ritek...