When I borrow DVDs from the public library, many are defective.
I haven't had any experience with Netflix, but I do borrow from the library.
Occassionally, I do have a problem with a DVD getting "stuck", but most times it's because there is dirt or grease on the grooves.
When cleaning doesn't work, it's due to someone being careless with the DVD and having put a bad scratch on it.
The advantage, to me, is that it's free.