If you’re going to use Memorex DL media, always use the 8x rated ones (RITEK S04). The 2.4x media (RITEK D01) isn’t as good or compatible with as many drives. Plus, these days, the 8x DL Memorex usually costs about the same as the 2.4x DL Memorex, so people should abandon the slower media altogether.
Now, none of what I said above applies to Verbatim. Verbatim DL media works, irrespective of rated speed, in every dual-layer burner on the planet. It is the best DL media on the market, period, and if you want the fewest problems and the best burns, go with Verbatim. It’s more expensive, but it’s worth it.