Any issues that the PS3 has with burned DVD's is usually the result of cheap media but sometimes the result of the software that was used to burn to begin with. This happens with all optical drives.
Well, the PS3 didn't have problems with these bootle... er, burned DVDs until relatively recently and the discs have no noticeable blemishes or marks on them that'd render them error prone (jJust some minor scratches and scuff marks but nothing severe or major) and brand-new (non scuffed/scratched) DVD-Rs have skipping problems too. Now, the skipping only seems to occur late in the DVD's video (near the end of the movie) and this is a fairly recent occurrence the last "major" thing happening to my player is a firmware/software download prompted to me by the PS3 a little over a month ago. (Either when I bought the Inception or the BTTF BDs) My DVD player has no issues with these same discs whatsoever.
My novice diagnostic skills tell me something happened in that lest update that causes the PS3 to have trouble reading the DVD-Rs near the center of the disc (where the "end" of the movie likely is). The player has no trouble whatsoever with store-bought DVDs or BDs.
And just to let you know! These DVD-Rs are of the TV series "Mystery Science Theater 3000" a show that encouraged viewers to "spread the tapes" (i.e. distribute the show) during part of it's run. The place where the discs that can be obtained only offers the discs that do not have an available commercial release, many of the movies featured on MST3K are public domain and, as an honest person, I buy the MST3K commercial releases when they hit store shelves. (Even though I already own the entire series.)
I own no bootlegged copy of any movie or TV series, my only burned discs are of these MST3K episodes and the Star Wars Holiday Special.