It really does depend. Old Phillips play +R only. Older Daewoos (+2 yo) suck with -r and +r and MAY play bitset +r -> DVD-ROM. Some Panasonics (older) have issue with writables. The first couple of models of Sony PS/2s had various DVD issues.
Fixes for video... The best one is to replace the player. New players start at $25+. Slower burn speeds can help as could lower compression rates, but this does not fix the problem. And using lower compression rates is a compromise that is counter-productive. Using prime media can help, but then again, maybe not. A BIOS upgrade on the burner may cut errors on a specific media and reduce issues.
As for which is better, more academic than practical. Get what your burner works better with. My Pioneer likes -R better. My NEC does not really care. And if you have to make allowances for your mom, sister, brother, do what I did; Buy them a new player for Christmas/Birthday/Groundhog's Day.
