DVD Ripper?

Has anyone used a DVD Ripper to covert your dvd's to various video formats to save them on your computer?? I am trying to make a video of my dad with various clips of us from VHS's that I recently burned to dvd's now my only problem is getting them to save on my mac to make a movie in iMovie?!?!? anyone have any ideas or help for me .. i am looking at Wondershare DVD ripper and 4Media DVD ripper. TIA