Absolutely identical!!!! Most comlpaints about dupes are due to using crap equipment, crap media and burning at too fast a speed. My dupes are as good or better than the originals. I walked into a high end shop one day and the manager tried to lay that line on me. I said not my dupes!! I challenged him to a blind test, he declined because there is no way he could pick the original except by sheer luck! I use an Apple G4 computer with an on board drive, and a LaCie external drive for DVD;s. I burn only at 1x sometimes 2x for dvd's The dupes turn out Identical and flawless!! I use any decent media like TDK or Verbatim for everyday use, and MItsui Gold cd-r's for the finest high quality music. Mutsui now has a Gold DVD, the first on the market, as far as I know. These disc used by MOBILE FIDELITY are superb! 300 year archival lifespan is incredible! Try mitsui.com or mam-a.com.
Slow down, don't be in such a hurry!! I also use a Furutech disc demagnetizer(which I sell), which makes discs sound fantastic, If you're heavy into digital and burning, the Furutech is a must!!! Also the Cardas test disc is superb, I use it routinely to clean the up the signal path with its demagnetizer tracks 1&7. This might seem like fanatical overkill, but you will produce consistenly high quality dupes by using this routine!!
Good luck to all!!