A number of the labs can be reset to state x using the various scripts. Often this does return the image to the previous state so a full reset is required.
I would like to the option added to be able to take snapshots.
Invaluable especially when you are studying for an exam.
We've talked about how we could do this off and on over the years, so it's already on our radar, however, we've not found a good way to accomplish this, yet. I know some classes are highly susceptable to a loss of work if the machines get borked (like the Satellite class). Unfortunately, at this time, I don't have an estimate on when such a thing may happen.
If there are scripts that are supposed to 'catch up' your environment to a specific state and they are not working, you should open a up a support case to report the issue. The Technical Support Engineer will write up a bug report that feeds into the content development team. This type of issue isn't going to be a high priority, but depending on the course, the do sometimes execute maintenance releases on courses, or review the outstanding bugs when they are taking on a major revision of the course.