For DVD+Rs, I have noticed a drop in quality from Verbatim. The last few batches I got in the past 1-2 years have exceeded acceptable error thresholds in Nero CD-DVD Speed. A Taiyo Yuden batch I got a year ago passed with flying colors. Fortunately it was a batch made in Japan, as I heard they were moving production China - not a good sign.
I'm looking for DVD+R DLs, and TY doesn't make those. Verbatim does, but the reviews say that quality has dropped ever since they moved production from Singapore to UAE a few years ago.