I've been using DVD Decrypter, This will make an ISO of the dvd and allows you to burn it with the latest version of nero. This will produce an exact copy of the dvd. The only draw back, is being limited to a single layered single sided dvd. A buddy of mine samples down the video bit rates a bit and strips out all the extra bonus junk to get longer movies to fit on 1 dvd. I've got a couple links around to some good step by step guides, i'll try and dig them up, but no promises.

http://www.dvddecrypter.com/