I've tried pretty much all the converting software out there and I still stick with Fairuse.
Fairuse isn't the best, but when you look at the whole picture {quality, speed, etc} it gives the best balance. Everyone is different and has different computers, so it's best to try them out and see what results you can get from each.
There are some programs that take 24 hours or more for a dvd to convert, but they give excellent results.
There are some programs that take nearly 100gb of hard drive space to convert a single layer dvd, but the finished results are excellent.
