I've heard some bad things about Meritline, but what I really can't believe is that so many people are recommending Supermediastore. Go to Resellerratings.com and you'll see 9 full pages of "very dissatisfied" comments.
Ritek is normally decent media; it's the best of the cheap stuff (although these days with the very best stuff being about 0.50 it's dumb to get anything else). Ritek always worked perfectly for me, but three different times I bought Ritek media from Supermediastore and it was complete trash. Apparently Ritek grades their media A, B and C, so all I can guess is that the stuff Supermediastore sells in a shrink-wrapped stack is C-grade. I've gotten 100-packs that the entire stack was unreliable past the 4,000,000,000-byte mark.
Since they were so unreliable towards the outer edge, I burned the last 80 of the discs without going past 3,950,000,000 bytes, but a year later most of them are totally unreadable.
I must admit that Supermediastore has some pretty good deals if you want DVD cases with your media. I've gotten three 100-packs of cases from them, and every time about 8 were broken. Looking at the comments, this is very common, and if you call to complain they blame it on UPS (even though the cases are obviously all scuffed up inside the box).
They've sent me Ritek G02 media instead of Ritek G03 media before (which was also pretty sub-par). If you look on resellerratings, you'll see that sending you the wrong thing is nothing new to these guys. Half the complaints are about them sending the wrong thing and then customer service hanging up. A lot of times they send cheaper media. There are many reports of them sending 2X instead of 4X, 4X instead of 8X, 8X instead of 16X. There are even complaints of getting used (already burned) media.
Anyway, I've had too many bad experiences with DVD-/+Rs, mostly from Supermediastore, and I have found several Verbatims that weren't recognized at all in old players when Taiyo Yudens worked fine. Lately I only buy Taiyo Yudens from Rima.com. The discs are so well made you can actually tell that they're more rigid than other DVD-Rs.
Rima.com is great. They're cheaper than Newegg and have a better selection.