You'll find most DVD's are DVD 9, dual sided (9GB), DVD-(+)R are single sided (4.7GB). So the problem you have using nero and such like the DVD you are
backing up won't fit on a single DVD-R, so not a lot of use really, and probably not as good as DVD X-copy anyway. As they are copy protected anyway you can't just do that as far as I'm aware.
Have a look at
www.dvdrhelp.com you'll will find all you need to know there.