I have a PlexWriter 40/12/40A and use Nero 6.
I just burned through a 50 pack spindle of Ritek Maxell 700 MB 40x CD-R's I purchased at Walmart for $15. These to be more exact: http://www.walmart.com/catalog/product.gsp?cat=3951&dept=3944&product_id=1978550&path=0%3A3944%3A3951%3A3955%3A4460
All 50 burned beautifully at 32x with no C2 errors and are readable at full speed.
Out of CD-R's I went back to Walmart and instead of picking up the same spindle, I opted for a multi-colored (jewel cases included) 30 pack of 700 MB Maxell 32x Audio CD-R's for $15. These were Taiyo Yuden. I figured these would be better since Plextor recommends the Maxell 32x for the 40x PlexWriter. These are suppose to burn at 40x, but I can only achieve burns equal in quality to the Riteks by burning at 20x. Anything above this is full of C2's and nigh unreadable.
Not quite sure if I should return these and exchange them for the Ritek spindle or just burn them at 20x. I really don't mind burning at a lower speed. All I care about is if this is an indication of a disc that will more than likely degrade sooner.