if you want the absolute best quality and time doesn't matter then you don't want to transcode at all. use an ENcoder like DVD-Rebuilder with one of the free encoders.
I can't help you out in that area since I normally use transcoders, but at least now you have something to search and gather more info on.
anytime you encode rather than transcode your quality will be better. dvd shrink, clonedvd2, and most of the programs mentioned throughout this forum are transcoders and do a VERY good job, but if you're adamant in getting it as good as you can get, re-encoding is the way to go.