DVC is not cheap and it doesn't work for everyone. Think of it as a way to prepay (and lock in the cost of) on site lodging for the next 40 years.
In general, DVC is a good value if:
* You visit WDW (or VB or HHI) at least once every other year and plan to continue doing so for the foreseeable future
* You stay in at least a moderate on site hotel when you visit
* You can plan your vacations 10 -11 months in advance of arrival
It is a better value for those who visit annually (or more often)and stay in a deluxe on site hotel.
DVC does offer its members some other discounts/perks/lodging options, but those are subject to change and are not guaranteed. If you cannot say yes to the above three "criteria", DVC may not be right for you.
Travel costs other than lodging (airfare and/or ground transportation, food and ticket media) will probably continue to rise and are a concern (especially for those of us not lucky enough to be Florida residents

). Your family will still have to have enough disposable income to cover those other costs as well as the cost of DVC.
We've been members since 1999 and still spend quite a bit of time in the parks. We have been buying annual passes and scheduling our yearly trips so that we get two or three one week trips out of the annual passes. We eat most breakfasts and some lunches/dinners in the unit to save on meals (and because portion sizes in most of the restaurants are too large for us

). We also take advantage of the discounts available to us as DC members, AP/PAP passholders and DVC members.
HTH a little. Good luck with your decision.