I think vobblanker is a great program as well; I used it in place of fixvts for a while until I started receiving various warnings about interleaving cells and marking the main movie as skip. I know it’s more in-depth than fixvts but all of those warnings that came with new encryption just gave me headaches. Every now and then I want to keep scene selection and various other options on select movies and I'll still use blanker. In the effort to speed up processing time and keeping compression low I usually just rip the main movie. I didn't start using fixvts again until I ran into something like macrovisions pagefile overload drm that was actually in the main title on a movie late last year. Ever since then I use fixvts just in case so I don't waste time compressing or waste 3 hours putting a faulty rip through rebuilder. When I finally ditch this POS koss system then I think I won't have to worry as much about fixvts messing with the dvd structure or giving my player a hard time.
The compression problem only happened on 1 or 2 different movies and was easily remedied by skipping fixvts. It was a while ago and I think I was using a dvdfab beta update so that could be the culprit as well. Sorry for the long winded posts. I haven't had a problem that couldn't be fixed one way or the other... I just saw this thread title and thought I would post my experiences and theories to see if anyone else could relate. I'm not trying to turn anyone away from fixvts, only explaining that it could possibly be the culprit for various processing or playback issues.