This is how I copy/back up DVD's:
AnyDVD + Nero - With AnyDVD the DVD is decrypted as soon as it's put in the drive.
Failing that...
DVD Shrink + Nero - I'll mainly only use this method, if the DVD needs to be shrunk in order to fit onto a DVD+R SL.
The above two seem to work the majority of the time, same quality and speed... Just depends what I feel like using.
Failing that...
DVD Decrypter + Nero - I've only had to use this once when a certain DVD wouldn't backup usnig the other two methods.