DVD-Rip speed is definitely great, however, I was surprised when my old Toshiba SD-M1502 drive was able to rip a DL DVD-Video disc faster than Plextor. I used a hacked firmware on the Toshiba that disables the 2X ripping limit.
Also, G@M3FR3@K, you may want to mention in your review that even though you didn't check the PI/PO rate of the DVDs using KProbe, that other people reported good results with RicohJPNR01, MCC002 and YudenT01 DVD+R media.
And if you get a chance, can you try burning some lower quality CD-R media (like CMC/Ritek) and see if it's successful.
Update: Just got off the phone with Plextor Engineering and they confirmed "Write Fail" problem with TDK (Ritek) CDR media and high C1/C2 error rate with CMC Magnetics (to be expected in case of CMC).
Verbatim(MCC) and TY seem to work well though.