Well, it depends. Are you looking to rip all the episodes into one big file, or do you want each episode in its own file?
If it's the latter, here's my experience. I just ripped every episode of Red Dwarf seasons 1-6 into separate files using DVD Shrink 3.2 and PSP Video 9. DVD Shrink allows you to remaster DVD rips, so you can pick and choose which titles/chapters you want to rip into VOB files. PSP Video 9 then lets you convert these VOB files into 320x240 MP4 video files at a video and audio bitrate that you can choose, including VBR.
So far, each 30 minute episode I've ripped converts into a 56-57MB file with excellent video quality and 128kbps audio.
It also helps to have a fast processor. I'm running an AMD Athlon64 X2 4800+ dual-core with 2GB RAM and each episode takes about 5-7 minutes to convert in PSP Video 9.