I have tried many DVD Rippers and would like to recommend this one to you, I always use it to rip DVD to my computer, the ripping speed is fast and the quality is pretty good. It also supports copyright protected DVD, you can use it to convert DVD to iPod, iPhone, Windows Movie Maker, PSP, iTunes, etc. Here is the download link
http://www.best-dvd-ripper.com/dvd-ripper-wondershare.html