I believe there is a major difference - it is to do with the dye's sensitivity to laser and the response that it creates on the laser light. Older slow discs tend to need more power to burn, have a low power variation margin, and when sped up significantly, the margin decreases. Also the laser has to be pulsed a special way to get nicely formed pits, with the amount of laser power needed, most pick up heads are not able to supply such power with the correct pattern resulting in a bad burn. The higher speed discs tend to use a dye which is more sensitive to laser resulting in better burn reliability since the allowed power variation is VERY SMALL at high speeds, the disc has to ensure this margin does not shrink further. Also, newer discs have better manufacturing, so dye coverage is probably more even allowing better burns, as well as the wobbled groove being slightly more visible to the burner allowing it to track at high speeds without error. Some older discs were also less balanced and suffer delamination after lots of use at high speeds - new media has been designed to cope with the rotational speeds that we demand now.
This is the info to the best of my experience and knowledge, contradict me anyone if they please.