At the moment, CDRs are produced under stricter guidelines and there are still inferior brands of CDRs and DVDRs. Getting ones hand on a sound duplication company that makes use of only specialized gear and high-quality media will result in a quality product. At any such place, the finished product is put to test in the midst of the duplication equipment to completely match the master copy.  In terms of cost and quality, and when it comes to CD/dvd duplication and replication, both comprise their gain and it is the customer who will pick the best method of manufacturing their products.