I have to start by saying I have always used Ridata media, and have NEVER had a problem.
The last 3 spindles or so (Ridata DVD+R DL) I have literally been burning 1 good, 1 bad... 2 good, 1 bad... etc. I am getting maybe 15 successful burns out of 25. I use imgburn for all iso's, and I even bought a new burner but that didnt help. I can burn dv-r perfectly fine not one coaster. I have never had a problem with dvd+r dl until recently.
Any ideas as to what the problem is, or am I just getting bad spindles lately?
the new Ridata 8x dl +R are no doubt made by the new Inverse Stack process (old/er burners cannot handle these discs even with a firmware upgrade). The new burner is in the right direction, just make sure it has the latest firmware. Also when using Imgburn, booktype the disc to dvd-rom.
I have the newest Pioneer burner (DVR 216D), and always burn DL media at 2x.
If one disc fails, I try again with the exact same media, and exact file, and then it works... I burned about 4 in a row successfully now, but just had another coaster... :S
Your current experience is actually quite common, with about half of a spindle of Ritek DVD+R DL failing to be good burns. These discs are problematic, it's not the drives. Switch to using Verbatim DVD+R DL media, for a better experience.
