Still use MacTheRipper and MPEG StreamClip, never took to HandBrake.
VisualHub gets used for TV shows, Miyu gets used for hardcoding subtitles.
All fly on my Mac Pro, VisualHub hammers all 8 cores, but I can encode an hour of video into H264 in just 6 minutes.
Still, like others have said, I could line up a half dozen DVDs to encode (H264) and play Civ IV or whatever at the same time. May slow the encode by a few minutes, but never caused any issues with the finished product.
Used to get issues with some DVDs, whether the Mac was busy or not, Alien 4, 1492, Mongol, The World At War from memory. Re-ripping made no difference, not even on a different Mac. These I would re-sync by hand (it's harder than you think - especially with foreign language films - of which I have a lot).