I did a spread sheet, too, and I could pretty much make it say what I wanted it to say.
For one thing, do I compare how I actually travel or how I aspirationally would like to travel?
I actually travelled like this (pre-
DVC):
Stayed in 1 luxury resort (AKV)
Stayed free on Marriott Points at the Marriott Orlando World Center.
Stayed free on Hyatt Points at a nearby Hyatt Resort.
Stayed in multiple cheap hotels in Kissimmee.
Stayed in multiple timeshares in Kissimmee with average rental for 2-bedroom at $85/night.
How I would like to travel:
Stay at the Grand Floridian every time. (But I am way too cheap to pay $750/night for a hotel room.)
So in my spreadsheet, if I compare DVC at VGF to how I actually travel, it never makes sense to own DVC. If I compare DVC to how I would like to travel (at Grand Floridian every time), I can make the numbers work.
Another huuuuuuge factor in my spreadsheet is that in the past, I did not come every year. If the economy was down, if I was out of work, if we were busy, we didn't come. This flexibility is worth a lot. I could cancel up to the night before in many cases. If my spreadsheet assumes 10 nights a year at VGF, I get one answer. If I assume that I come once every three years if the economy is good, I get a different answer.
So once again, for us, it became an emotional decision.
An addition to the emotional factors I mentioned before, there is the multigenerational factor. I first saw Disney World when I was about 12 years old. I then saw it through the eyes of my children. And now I get to see it through the eyes of my grandchildren. And I experience each attraction not only as I see it today. I also experience it with the memories of being that 12 year old. And I can afford it, so we bought.
One more comment on my long dissertation on discount rates and inflation. It should be clear that it will never make sense to buy DVC at any reasonable discount rate if you are financing through consumer finance rates. Disney was offering 16% when we bought, which is somewhere between double and 16 times a reasonable discount rate.
You could never make a spreadsheet break even at that rate. (At least for buying direct....I would not say categorically that you could not make it work for resale, but I have my doubts.)
Finally, best of luck as you make your decision. We are a year into it and really enjoying it.