I've used Handbrake for a while with mixed results. The good news is that it's free. However I've had trouble converting about half my DVDs, maybe it's copy protection. And sometimes the ones that do appear to convert properly, the audio is out of sync with the video. I decided to go ahead an pay money for a converter and purchased the Daniusoft converter for $20. I couldn't be happier. It converts all my DVDs without a hitch, is easier to use and faster than Handbrake. I guess you get what you pay for.
I like Oplayer on the iPad for playing them back. I can transfer the videos via wifi from the computer to the iPad and not have to use iTunes.