I tested the DVD that I burned at 16x speed on various DVD players, and it seems like the older DVD players can't play it. The menus come up, but when you select them, it doesn't play. I have a Mintek portable 7" DVD player, which I bought 2 years ago, and it plays fine on that. My computer DVD ROM plays fine as well. I guess the newer players are better for DVDs that have been recorded at high speed.
I burned a Lightscribe label with it. Seems like it still takes a long time, the Lightscribe technology is still very slow! If you can burn a CD-R at 52x speed, then obviously the speed of Lightscribe can (and should) be improved. There is talk about how it uses the same laser to burn the label, but does it wear out the laser faster? I don't know. Perhaps they should use a separate, more powerful and wider laser to burn the lightscribe label. This would speed up the process and relieve the primary laser of burning the labels. After all, lasers are cheap now, right?