"space-shifting" my DVD content for viewing on my portable devices has led to a generally easy combination of software to use that is freely available, light-weight and powerful enough for most tasks. Since the legality of DVD ripping for personal use (much like ripping your music CD's to listen to on your MP3 player) varies from country to country, check with your local jurisdiction. In fact, in some countries it is even considered illegal to download or own software that bypasses CSS!
The steps involved in converting your DVD's to MP4 are relatively simple. Once "unleashed" from the DVD player, you have the freedom to view your movies on a tablet, phone, or your TV-media player (WD TV, Roku, Boxee) and so on. The first step is to copy the movie to your hard drive using DVD Decrypter, in a way that is decrypted and can be encoded properly. HandBrake doesn't seem to handle this on it's own, perhaps for legal reasons it was not allowed to include decrypting code. However, it can deal fine with unencrypted DVD's (which are almost non-existent anyways). When I tried to have HandBrake read directly from the source DVD in the drive, it would always complain or even if it did read properly, the movie would come out with tons of strange artifacts and jitters which made it unusable.
So with your VOB files ripped successfully to your hard drive using DVD Decrypter, you can set your source in HandBrake to the directory containing your VOB files. It will successfully find your files and let you encode it. I generally use the Regular Normal setting which is good enough and leads to a file size about anywhere from 650 MB (1 hour 17 minutes) to about 1.5 GB (1 hour 50 minutes), depending on the length of the movie and complexity.
Regarding software versions, you basically have no choice but to use DVD Decrypter 188.8.131.52 because it is the last version available and is still very old. The developer was forced to stop developing this software due to legal action, but newer versions were merged into ImgBurn but which lacks the decryption functionality, essentially making it useless for transcoding (it is only good for copying your DVD to another DVD to play on a DVD player). However, you can use special drivers with ImgBurn to decrypt on-the-fly if needed.
HandBrake is up to version 0.9.9 but I had problems with it on my Windows 7 32-bit system. Therefore, I found that 0.9.8 (available from SourceForge) is more stable and works better. So for now my power punch combination is DVD Decrypter 184.108.40.206 to copy the VOB's over to the hard drive, and then HandBrake to convert over to MP4.