Did your friend get them from the same store? Could very well be the same (bad) batch, you'd have to check the QC/production run info in the center to find out. Or perhaps I'm just simply fluking out and got all the ones I have here from a "good" batch?
The guy you are pointing to at cdfreaks bought his disks 4 months ago... so it couldn't really reflect on the current/new ones (now), does it? Are they at least using the same burner model(s) as yourself? Have you even considered the possibility that the effect you are seeing has something to do with your burner, or for that matter it's burn history of same media code but differently producted media? One thing to consider is looking at his scans they do look almost exactly like the post burn scans I have of MII disks.
I don't have any long term results as of yet with these dual layers, unfortunately. But here is what some of my burns looked like (for 360 related ones at any rate) and why I justify suggesting the more expensive Verbatims. Burned on pio 212d scanned on benq dw1620. For whatever reason, I don't have any memorex scans on my drive at the moment, the two I tried to burn for the 360 gave dirty disk errors and some very unnerving noises from my 360's drive until they did.
Given this example of
current local pricing ($40/15 fuji, $50/15 memorex, $58/15 philips, $55/20 verbatim), the verbatims are definitely the best value for the dollar (especially if one waits for a sale and can get actually MIS packs at that time.)
24fujiD01 - fuji label 8x disks (of a 15 pack only 5 burned like this without any read errors when fetching the data back,
this is what the other 360 burn I did looked like) - seems to work OK in the 360 until the drive heats up (.5-.75 of an hour, I suspect the laser is a bit weak.)
24xMIIverb - the MII 2.4x verbatims I had gotten locally at christmas time, this is one of the
better scans.
8xMISverb - these I got for a mint from blankmedia.ca, the 8x branded ones (haven't had any problems with these yet), burned at 2.4x
4MISnewVerb - these I picked up locally with the purple packaging when they were on sale recently (25CAD for a 20 pack), this burn was at 4x. I can say I was getting slightly higher PIO failures
burning at 2.4x, but none of the disks have been a coster aside from the one with surface/dye issues I simply won't burn to find out.
Any rate, use the warranty it is there for many reasons besides just giving customers peace of mind - if most don't do so when they run into problems then the company will continue to go on selling defective media with next to no chance of finding out there are problems somewhere along the way, the result being generally that they would continue to be unreliable in your eyes despite such a great warranty.
Keep in mind as well, like I said before the whole thing is somewhat subjective. Even if you have the same burner as I, it's history can impact it's burn quality. After a few disks I can no longer burn my ritek cdr, nor the fuji disks, without problems. I wish you all luck in finding the "magical combination" that works with your burner and 360 drive, I'm pretty happy with the one I found for myself.