You can use something like DVDinfo or the analogous app that comes with Nero to scan the DVD and tell you if there are bad spots on the disk after the burn. But unless you have the original ISO that you made the burn from, you have no source image to do a data compare with. The Decrypter default is to verify after the burn. Unless you changed that, you probably did.
Anyway, why bother with this. They are just backups. If the cheap media gives you problems down the road you still have the original DVDs to make fresh copies from.