If you want ISO format, you'll have to buy at least DVDFab Express.

Don't be greedy now; unlike LIGHTNING_UK!, Fengtao is a commercial operation; just be thankful that they have been willing to provide a free ripping alternative updated to deal with all current dvd protections.

[Btw, you can always use Image Tool Classic to convert your ripped files into iso format and then burn the iso with Dvd Decrypter anyway.]