i had gone to WDW since it opened, but we started going as a family every year around 1989.
our first WDW family vaca was off-site: not for us (all of having to leave if one person needed/wanted, dealing with traffic & parking lots, nowhere near as relaxing, kinda like 7 "day trips" instead of a week-long
vacation).
so we started staying at the mods, then deluxes, and DVCs (i was a DS CM at the time, so usually got 50% off rack).
we fell in love with the BWVs

my DB/family & parents also found their favorite in the BWVs, but were paying rack for a 2-bdrm (over $500 plus tax a night) every other year.
i calculated our real cost per point (PP purchase price, maint fees over the course of the contract), and found that purchasing DVC would save us a least 60% - usually more - over rack. (PP price and maint have risen, but so have room rates).
we bought in 1/1999

aside from the above, deciding factors were:
- DVC prices had risen since they first opened OKW. other timeshares i researched lost significant value as soon as purchased (we could sell our points today for
more than what we paid PP, and have taken almost 25 years of vacations for less than our main fees).
- as our kids grew, our vacation habits changed. as a family of 4, we would stay 1 week in late august/sept (1 bdrm). we now go 10-12 days in may (DD & i), and another 10-12 days in oct (DH & i) - both in studios. a fixed week/unit size wouldn't have worked for us.
- we were still able to vacation after DH's company (wall street) downsized. we rented out some of our points to pay for passes & airfare.
our only regret is not having all our (400) points at the BWVs. after staying at most of the others, we prefer the BW's quiet elegance, decor, views, CMs, entertainment, food and drink

options, Community Hall, easy walk to 2 parks & mini-golf.....lots of activities at our fingertips, as well as a myriad of more sedate, relaxing options. the BWVs have gotten much more difficult to book at 7 months out.
we would rather have less years at a resort we love, than buying a longer contract, & spending those extra years longing to stay elsewhere - that's just us tho
aside from "buy where you want to stay", i would recommend resale for he savings (it wasn't an option when we purchased).
do your research, feel comfortable with your decision (financially, time-wise) before putting a penny down.
then sip the kool-aid & enjoy