We had a Hilton timeshare for almost 10 years. It's a point system that we can go to properties available through RCI. The points allows us to get about 2 weeks of 2br units each year. In our situation(too many kids) we consider it a good deal since we save tons of money on foods and the quality of environment is way better than, say, staying in a motel. Also it fits our philosophy to have quality family time together in a relaxed way.
If we didn't use the points, we saved them for the next year or gave to relatives.
Time-share is a way-of life thing, just as RV. So it depends on the person.