I doubt you’ll find a program that makes better DVD5 copies from DVD9 than DVDRebuilder. In fact, I’m certain of it. Since it can utilize CCE or ProCoder or HCenc as encoders for this process, I don’t believe there is anything comparable.
Transcoders will always be inferior in the way they process the dvds. It is simply the way they work. Most people can’t see these differences in their backups unless the movie has a lot of compression, or unless you are viewing on a large screen, or if the movie has a lot of action sequences. Then the higher quality from the encoders will show through.