These are rated as B grade but I burned loads with no losses, no worse than Taiyo Yunden or Verbatim. Okay, these are better but not by much if you have a good burner.
They are perfect for DVD Video when I burn 4.35 GB of data. No jumps or glitching - so perfect for the job.
I recommend burning at 12x or less, ideally 8x. Burning at 16x is okay, but the Ritek F1 dye it a little harder to write to than most. For the sake of a minute per burn, you will have no losses and save £s on this 3 for 2 deal. In my experience most lost burns are hardware or compatiblity related. Whenever I've lost a discs it's been something else.
Conclusion - 100% okay if you burn a tad slower. Very good savings on this deal...