For the most part, frameserving from Vegas to Handbrake works beautifully and gives me the best web publishing renders I have ever seen.
The one exception is if I try to re-render a portion of a DVD by dragging the IFO onto the timeline. What happens is that the frame-served render hums along up until the point where there is a division between to VOBs and than stops at that point never to get past it.
Regular IFO renders work fine through the joints.
I edit a sermon out of a DVD and post it once a week and I would love to be able to do the edit in Vegas. Right now I'm doing it in Womble MPEG Wizard, but there is a little glitch at the VOB joints. Anyway, since this is a regular occurrence, I have tried frame-serving IFO edits quite a number of times, and it always fails in exactly the same way: stopping and not recovering at the VOB joints.