I have a Pioneer DVD-RW DVR-110D and have problems only in the form that I can burn the blanks only 4x. Otherwise I can not see any mistakes. The disc's started running reliably, regardless of the format, on my Toshiba but also on other devices.
I had between a 10 of Conmark + R 8x, Sony spindle -R 16x but it was half scrap, after which I returned to to Platinum and the 4-way take speed into account. I have from the last 50 spindle half consumed, all previously properly.
By the way: The quality of Conmark blanks used decreases. I no longer recognized since 5 years in use and some will suddenly, so I had to play around the rest on Platinum.