personally, I like dvdshrink..it's at dvdshrink.org. It's free. It's failsafe. I'm satisfied with it. X-Copy is good if you want to make a copy of a DVD that already fits a 4.3 gb, single layer blank disk. If you have an actual copyrighted movie, it could still fit onto a 4.3 gb disk, but more often than not, it won't. X-Copy can take care of fitting the movie on the disk but you don't have any re-authoring options that dvdshrink does.
on shrink, I can determine the sound I want. For instance, I can take out AC3 sound and have only DTS or 5.1. This saves space. I can also edit out anything in the movie I want, including the extras, the previews, even the FBI screen at the beginning of the movie. Usually, to save space and enhance the quality of a movie over, say, 7gb's, I'll remove everything and just record the movie in the highest sound quality it has available. Then I have a movie that's pretty much exact in every facit. Dual burners and dual disks make shrink unnecessary except for it's copyright ripping ability. But if that's all I am doing, I'll use dvddecrypter, cause it's free and has the ability to rip anything. The problem with the dual shit is, it's new and expensive, at least the disks are.
FYI, if you copy an 8gb movie, like Saving Private Ryan, on to a 4.3 gb disk as an exact copy (meaning you shrunk it) without taking out a thing, you're gonna have a compression ratio around 50% and the picture quality will suck.