I had some skipping, hesitating videos after I burned them using the Dangerous Brothers beta firmware and bitsetting utility. I don't know if that was the problem but since then I have had nothing but excellent luck after I did the following:
I flashed my NEC 3500A using the "factory" firmware off of the Mad Dog Multimedia web site.
I used the "factory" bitsetting utility from the Mad Dog Multimedia web site to set my DVD+Rs as DVD-ROM.
I burn only Taiyo Yuden 8X DVD+Rs (both Taiyo Yuden and Japanese Fujis).
I make sure that my Nero burns the 8X disks at 8X or even slower at 4X by setting the burn speed at 8X or 4X - either way not any faster than 8X.
Doing this I have had excellent luck - no coasters.
I say stick with the factory stuff until one of the hacker-modded firmwares proves to be both better and faster by unanimous agreement.