Longevity of DVD-R and CD-R (Was MagTapes)

Ironically, the DVD-R media that I've had the best luck with -- and my experience with this brand has been superb, no failures, perfect burns, and perfect subsequent readability -- is a bargain private-label off-brand. It's "K-Hypermedia" brand, sold by OfficeMax (and, very rarely, by other retailers). I've gone through over 10 25-packs over a period of 2 years, 1x (which burn well at 2x on Pioneer burners) and 4X, and my experience with these has been wonderful. And they are cheap, sometimes on sale for as little as $5 for a 25-pack (more commonly $10 for a 25-pack). On my Pioneer A04 burner, I could burn the 1X media at 2x by default. On my A08, I had to get "hacked" firmware to allow me to select any burn speed with any media. But in both cases, 2x works fine for the nominally 1X media. I'm now also using 4X media with equally good results. [They have a DVD+R product as well, I have used one spindle of it, it was fine, but my experience suggests that when given a choice, "-" is the format to prefer. Cheaper, more available and more likely to be readable, not withstanding that the "propaganda" says just the opposite.]