I've used iRipDVD. And it isnt too bad at all. Was a bit slow, But got the job done easily enough. The only problem I had with it, was when ripping from DVD's that have more than 1 film on them (These are rare, granted). It would only rip one, instead of all of them. And there didnt appear to be any way to get it to rip the others.
Other than that, if you dont mind AVI's, it's good.