It's definitely worth looking into. Without really knowing your vacation patterns, type of room you want to have, and so forth, it's hard to really put it in black and white.
Basically with
DVC you pay a fixed up-front price for a number of points. You then receive that allocation of points to use every year for your vacationing. Let's say you buy 150 points (which is the minimum) with a February Use Year. Every February 1st, you get 150 points to use. If you don't want to schedule a vacation one year, you can bank your points to the next year, giving you 300 to use on the following Feb 1st.
After the up-front price you then have to pay annual maintenance fees, which run about $4 per point. So, on 150 points, the dues would run about $600 per year.
The number of points you need for a given room will vary depending on a number of factors including resort, room size, season and even day of the week. There is a point calculator and
point charts linked on this website that you can use to try and determine how many points would be right for you.
But just to illustrate, with 150 points you could spend 12 consecutive nights in a Studio room at Saratoga Springs about 5 months out of the year. A studio is comparable to a WDW Deluxe resort room with a queen bed and sofabed, in-room kitchenette (sink, fridge, microwave, toaster, coffee maker), balcony and access to free laundry facilities.
It will probably take you 6-8 years to break-even on the initial DVC investment. That's the point at which your initial investment plus annual maintenance fees equals what you would have paid if you had been paying cash for each trip. But after you've exceeded that breakeven point, you are vacationing at a fraction of the cost. Paying $600 per year for 12 nights in a deluxe room is probably a little better than the rates you got at the Poly, eh?
Potential downsides:
* From a practical standpoint, if you buy into DVC you need to accept the fact that you will spend the majority of your time at a DVC resort. That means Old Key West, Saratoga Springs, the Boardwalk, Beach Club or Wilderness Lodge. DVC does allow us to use points for non-DVC moderate or Deluxe resorts, but the trade-in costs are ridiculous. The Studio room I mentioned at SSR is 11 points per night for a weekday. A comparable room at the Poly is about 30 points per night.
That's just the nature of the beast.
* For a family your size, you would tecnically need to get a Two Bedroom accommodation. 2Bs are GREAT rooms, but they also cost a lot more points per night than, say, a studio. A 2B has a full kitchen, living room and two separate bedrooms. The master bedroom has a king size bed with whirlpool tub. The second bedroom will have either two queen beds or one queen and a sofabed. Each 2B has its own washer and dryer. They are fantastic accommodations, but they run a lot more than 11 points per night.
Some have reported that DVC increased the maximum occupancy on a One Bedroom from 4 to 5, which would accommodate your family. 1Bs are great, too. They still have the full kitchen, LR, balcony, W/D, whirlpool tub. But they were designed to sleep 4--they have a king bed and a pull-out sofabed in the living room. DVC resorts do not provide cots or rollaways, nor do they provide linens for more than the posted occupancy level.
Good luck. Ask more questions.
