Is DVD good to use for an editing master?
Not really- MPEG-2 video might look extremely sharp playing off the DVD but it is highly compressed. Most NLEs cannot edit MPEG-2 video so you would need to recompress it back to DV or whichever codec you normally edit with. You might find the quality hit and time involved detrimental to your workflow. DV or Digibeta tapes are still the better mastering formats. DVD can make a fine viewing copy though.