[fratres]

Exactly, lufcfan, that is the thread I found when I tried to find info about +R (it´s linked in the UISticky, isn´t it?), and it says:

Success with DVD/DVD-R on the PS2 is, first and foremost, a question of reflectivity and the causes of poor reflectivity.

So I thought there is maybe no difference between the two standards (as long as they have the same reflectivity) for lasers that are able to read +Rs. Charlie also says the following:

DVD+R is the write-once version, also with a polymer dye so that the burned result is narly identical with DVD-R. The "nearly" term reflects the fact that newer read laser mechanisms are more accurate and can resolve the small differences between DVD-R and DVD+R arising from the fact that DVD+R can be burned at 2.4x because of the wobbled groove.

Maybe resolving these small differences stresses the laser more than just reading a -R?
I also found http://www.fileforums.com/showthread...=DVD%2BR+media
where Headly says +Rs are as good as -Rs as long as you use quality brand. So obviously several different opinions.