Rip DVD to ISO

I would like to find an app that can rip a DVD to ISO and also remove all the unneeded information like menus and unnecessary languages, subtitles etc, as to reduce the file size to store on a external hard drive.

DVDFab seems to work as I wanted by removing the menus and such, though it gives me no choice to edit the format like Disk Utility, and so rather than creating a .cdr like disk utility I have an .iso file, what is the difference, how will this affect me?
If .iso is fine to use for creating backup DVDs I would rather use DVDFab over Disk Utility for practicality, though I need some reassurance, will .iso suffice?
and finally will any particular programs create a lesser or better quality copy of the DVD in a disk image format?

DVD to .CDR

I have already copied a DVD with disk utility using the image format DVD/CD Master but now I get a message saying permission denied when I attempt to copy the DVD again, is there a limit on how many times I can copy a particular DVD in this way?

Update
The DVD in question is now copying through Disk Utility without any changes made by myself. Any idea what the issue may have been?

Also, what is the difference between .cdr and .iso and how will this affect me?

Merged threads - no need to start a thread to elaborate on an old one.

Is this a commercial DVD that you've ripped?

Van, this is his 3rd attempt to discuss the same subject. both other threads have been closed. The first two were about copyrighted material.

So it is. Thread closed.