Well I've been a big Mitsui user in the past.
It is true that Mitsui has a higher playback rate as a average cd-r.
But so does Verbatim's AZO. The funy thing is drives that fail with Mitsui seem to like AZO quite some times and drives that fail with AZO sometimes work excellent with Mitsui. It depends on the question why is it failing. (overreflectivity, to low reflectivity)
Now these days MAM-E/A whatever you call them makes crap specially when it comes to dvd recordables.
Now about cd-r's. Here In europe MAM-E has dropped the quality big times still they make some good disc's. Which are the Mitsui Medical and Mitsui Pro Studio stuff. These disc's can compare in quality with old normal Mitsui consumer media. Now the point is that these disc's are costing as twice as much as Verbatim Metal AZO disc's(which can also last longer as 100th years according to there manufacturer) , three to four times as much TY media. And 5 times as much as FUJI media. And the point is all these media seem to perform just as good or better.
Mitsui has a great PR machine. I can remember the graphs ot HongKong AZO media, and Cyanine (not the metalized stabled version TDK and TY use these days) (Probally Princo cyanine !)on the mitsui site to show the superiority of there disc's.
Also Accelerated Ageing tests and UV exposure tests are quite questionable themselves.
Still there is one good side of Mitsui they do have a lifetime waranty.
Which means the time they should work according to Mitsui.
Now they don't make any trouble for replacing the media. Still replacing the media is to much fuzz for me.
Why isn't it better ?
1 pthalocyanine the best dye available ? Well why is MAM the only companny which uses it for DVD recordables. It is cheaper as AZO so why use AZO or a cyanine azo hybride !
2 Ehh don't we forget that good old basf/emtec(YEP the crap) companny and TY have something called Ceramic coating. Remove the upperlayer of your disc and you can still read it ! If I remove a Mitsui's Diamond coat toplayer the disc is ruined.
3 Don't make me laugh but Mitsui isn't consistant these days when it comes to quality. Infact it is as bad as Ritek or as MCC media on a Lite On 48125W. (