We are in the process of purchasing a resale through TTS so I'm not an expert on this but here is what went into our thinking to finally purchase
DVC:
We needed to have a tax deduction so using home equity was a factor. With the possible current tax hikes for us, we needed to use some equity and get the write off. We go to Disney every year or
DCL every other year so we really should have done this years ago -- it would have paid for itself but we were young and stupid. Silly us!
The yearly maintenance fees are what you would pay almost anywhere you "owned". Though a little more expensive, part of them (possibly 22%) are tax deductible as they go towards property taxes. We had looked into purchasing a "lake house" in Wisconsin but the maintenance fees in the community along with me having to keep it up were just not what we wanted. A lakehouse isn't a vacation to me -- just my opinion. I like to vacation and I like Disney, even if I don't go to the parks so that's a factor.
Perks -- not sure on all of them. I know there's a discount on the Annual Passes, restaurants, etc. Free valet if I remember. To us, the biggest perk is being in the deluxe resorts with a kitchen. My kids have food issues and the full kitchen is valuable to us. I like the 1 and 2 bedroom options.
A timeshare of any kind is a "paying it forward" for vacation. We vacation and like to vacation at Disney -- so that made our decision. We're spending the money anyway so it gave us a tax write off with the equity loan. We could have paid cash outright but the write off of using the home equity was important to us.
I regret not doing this years ago as we always end up at Disney. Didn't realize that 20 years ago when we began the family but boy -- we would have save $$$ doing it back then. It all depends on what your vacation habits and personal choices are.
Hope that helps.