Keep in mind with DVC, they are not deeded so Disney gets to take them back in a few years. The marriotts and Hiltons are deeded so you can pass them down to your family.
99% of the time, I don't think timeshares work. The maintenance fees are too high, especially in Orlando, and you can rent a time share week for the same maintenance fee money or sometimes less.
Also, there are fees everywhere, join RCI, annual fee, trade at RCI, another fee. The final cost is just not that good.
That being said, i own a timeshare in Cape cod. We visit that resort on our summer week every year. We pay our $400 maintenance fee (cheap compared to most) every year and I never trade. To stay a week at the cape it costs $1000+ due to its short season. We picked up our unit on eBay and it will pay for itself in just a few years so the math works in that specific case.
My two cents.