I've been using my G4 Mac Mini to rip my DVD library and have to say that I've been less than impressed with the time that it takes to rip a DVD. Today I decided to try the beta version of MediaFork to rip a DVD on my MacBook Pro. Previously I have ripped DVDs using the standard ffmpeg MPG4 encoder at 60% constant quality and have gotten movies in the 800MB-1.5GB range at a quality that's certainly acceptable using the AppleTV. However, I did rip one DVD on the mini using the H.264 encoder and the quality was much better, but it took around 11 hours to rip.
When I put a DVD in my MacBook Pro today and set MediaFork up to use the H.264 encoder at 70% constant quality, it ripped the DVD in less than 2 hours (film length of 2.25 hours), which is just incredible. MediaFork is compiled as a universal binary, so it obviously takes a lot of advantage of the capabilities of the Intel processors.
In conclusion: I'll be ripping my DVDs with my laptop until I get a Core2Duo desktop.