The consensus seems to be that BenQ is a lot better with +R than with -R media, but it isn’t bad with -R media.
My NEC 3500 however was a lot better with Verbatim DataLifePlus DVD-R 8x (MCC 02RG20) than my dad’s BenQ DW1620. This media is my absolute favourite for the 3500 but I don’t know if the 3520 is as good as the 3500 with this media?!
Why don’t you take a peek in the BenQ/Philips forum and form your own opinion from the Media scans posted there? Most scans are +R media however.
Is there any reason you prefer -R media? The BenQ has automatic bitsetting of DVD+R media to DVD-ROM Booktype, so it should be at least as compatible as DVD-R media with DVD players, and the BenQ prefers most +R media over -R media.
No drive will show you any “absolute truth” when scanning media, it will just show you how well it can currently read the disc. My opinion however is that I want to see at least two drives reading a disc perfectly before I’m sure I have a good burn, and I will prefer a good Read Transfer test over a good PIE/PIF test any day of the week!!! (But I want both).
The BenQ will show Jitter values, which the NEC 3520 drives can’t show (at least not with current firmware), but with the NEC 3520 you have the choice of scanning PIF at either 1 ECC (correct according to ECMA standards) or at 8 ECC like the BenQ. The BenQ will only scan at 8 ECC.
The 3520 will read burned media at only 8x with official firmware whereas the 3520 will read +R/-R media at 16x. With an unoffical patch however, the BenQ will read all DVD media at 16x, even DVD+/-RW media.
The BenQ has some interesting utilities (QSuite) that allows you to scan discs for Tracking Erros and Focus Errors (TE-FE Test) before you burn them, and also to change Booktype of DVD+RW media AFTER it has been written.
The BenQ has MediaCodeSpeedEdit for modifying firmware, whereas the NEC 3520 has Liggy, Dee and Quikee.
Since this question was posted in the NEC forum, I expect to hear a lot of NEC praising from you guys…