Beirut, you might also want to research the fact whether or not the DVD player can play home grown DVD’s and backups. I know that Sony DVD players were built so that they couldn’t read those, and sales suffered as well as people who bought those. I always backup my most important DVD’s; to some I add subtitles that are not available on the DVD to begin with. I find it stupid to consider that only bootlegs are the sort of home burned DVD’s that goes around.

Oh, and expect to have some trouble with DVD-R’s with almost any DVD player.

But, on the other hand, to the primary issue, I would not absolve the rental DVD’s from all guilt. If the new DVD from the store runs well, and your rental DVD does not, the answer is pretty much clear; ruined rental DVD.