(just to see what other people are successfully burning at) i tried 8x, but errors. (skipped) now.. 4x
I burn at 8x - on 8x media and sometimes higher on 16x media mainly using Taiyo Yuden or Verbatim. Burn at what speed works for you and your set up. Also using quality media can make a big diff too.
i give penty of time to this part of the process, 2x all the time, it does take 20 minutes or so but it is safe.