A fair number of board members warn people about the quality of cheap media, more often than not they're referring to Princo DVD-R.
I have burnt a number of TDK+R 4 speed (RicohJPNR01) discs and they result in a basically ok kprobe (PI maxes at about 100, PO maxes at about 12). I have some problems where my own DVD player (Pioneer DV525, known to play anything) sometimes has problems, producing artefacts, or locking up (although most of them play without problems). My in-laws (Cyberhome) DVD player is unable to play most of the TDK's. Only a few of them are even recognised (not a booktype problem, the player is able to play + disks) and my brother in law's PS2 also has problems with some scenes of some of the movies. Even though these are discs that give a good KProbe scan. A decided to take a test and bought a single Princo DVD-R 4 speed. Just to see what it did. Burned a movie and did a scan. Scan is not terible, but certainly not good. PI values of around 350 average, PO never higher than 12. This disc plays perfectly in my Pioneer. Decided to buy a spindle and burnt a movie for my in-laws. Guess what: Disc plays perfectly. Gives an ok KProbe as well: PI max of 300, PO max of 10. Don't know what this disc will do in the PS2 though. The thing is I always read bad things about -R burning and that the best results should be obtaineable by using +R media. I read a lot of people complaining LiteOn should get their act together on their firmware when it comes to -R.
Furthermore I buy a german computer magazine, called C't which I think is the best computer mag there is. In their 5/2004 edition they spent an article on 8 speed media and 8 speed burners. They have high-end equipment with which they scan the discs. They tested the quality of -R discs (Maxell, Taiyo Yuden and MCC), +R 4 speed discs, which the 811 burns @ 8 speed (Taiyo Yuden, Ricoh and MCC) and official 8 speed +R discs (MCC, Philips and Ritek). Guess what, they found the best quality on the -R discs, especially the Taiyo Yuden and the MCC discs. They even advise people to use these discs over +R. This kind of contradicts the things I read on this forum, but is kind of in line with my own findings. Even LiteOn distance themselves of KProbe results. C'T used HS0K as firmware, by the way.
To conclude (and I know this has been said before) take KProbe scans with a large grain of salt and (at least for me) Princo gives results that are good enough for me, considering they cost about half of a quality brand (with which I have troubles getting recognised in different players). I know with Princo the quality varies (even within the same batch), some people even burn complete coasters, but you might be able to test one of a spindle, like I did.
If people are interested in a scan of the article, PM me, I might scan it.
If nothing else this shows that users should make up their own mind as to what is defined as quality and the media they are happy with.