Okay, I've let the prog crunch the DVD all night, I can't tell for sure how long did it take to complete compressing the DVD but this morning it was done and I could play with the final result.
"Chronicles Of Riddick" dropped in size from 4470 MB to 1816,2 MB with about 10% drop in quality. I have chosen NOT to compress any audio and I've set the quality slider in ratDVD to 100. Oh, and for all the people out there which are concerned about having to use WMP10 I have great news! You don't need it to convert and play .ratDVD movies!
Nowm about the movie. ratDVD managed to keep the original structure intact, that includes all the features available on the original DVD. That is great! AC3 sounds were there, too, I managed to play the .ratDVD file just fine on my Genius 5.1 HT Audio System and it's surround, baby
The only drawback is the loss of image quality, but it's compared to compressing from DVD to DivX or XviD so that shouldn't be such a big issue. I'm not sure what will happen with the image quality after decompressing this movie to DVD format again, maybe I'll do that tonight and see what happens. Having both the original DVD and the (re)decompressed DVD at once might prove to be a good occasion to compare image quality and see if it's worth compressing our movies.
So far, this new movie format is promising, I simply love the idea of having the entire DVD in a single file (together with menus, extras, bonuses, etc.). But the developer should really-really try and optimize the compression algorythm, the compression takes too damn long to please...