It also depends on how much time you want to spend on the backup; if you want to get rid of warning and/or other extras or you want to do a little re-authoring like starting the movie immediately or from the root menu, etc.
For me, if I have just single layer DVD-Video, I use DVD Decryprer first ISO-Read, than ISO-Write. Simple fast. I do not care to copy everything. Time is more important.
In case I do want to re-author a single layer, or for all dual layer (to back up to single layer media)
I first use DVD Decrypter to rip in File mode.
I then use small program TitleSetBlanker to remove the titles I do not want. I do not need the full power and complexity of VOBBlanker.
I verify every stage with free program Windows Media Player Classic where you can open the VIDEO_TS.IFO file play the DVD and see what will be the final result, or you can also open the individual title IFO with this program and see what is the individual VOB like, if you want to keep or blank.
When happy with the results, I load DVD Shrink for removing audio and subpictures, and setting more compression for all menus and extras, and hope to get 85% or better in the compression of main movie. DVD Shrink makes ISO file. I like to burn later in separate step.
If I want I can mount the result ISO in Daemon tools and check, also playable in WMPC, you hae to open "CD drive" menu here.
I burn the result ISO with DVD Decrypter.
This is just me, others have different ways, I hope we all share what we do.