I've no doubt noticed undependable burns at higher speeds. If your like me i usally dont watch my movies until I have already taken the original back. therefore If I come across a bad burn then im just out of luck. I actually posted a like thread several prior to this one. When I burn higher than 4x i have pixilation in random places during playback. However its not always in the same places. However Ive never experienced any probems at 2x. Im using a brand new sony dru-710a burner with the latest firmware and still have the same issues. If I were you I would run some test on some movies that you already own and see how it works. I would also keep in mind the media that you are using. Once you find the burn speed suitable to you and the particular media that also produced the dvd at those speeds, i would stick with that process. However there are others that know alot more than I do about this topic.
I haven't noticed in the quility or audio of the burn speeds. I burnt movies at 4x and 8x and they both worked. I haven't seen any difference but it might be something with the burning speed.
