Just piping in, in support of this thread.
I've priced out our spring break trip to WDW - 16 nts. (7 AKV sav view studio and 9 SSR studio) and it would have cost just under $9,200. Using about a year and a half worth of points/annual dues, the cost to us is about $1,700, so ultimately we're about $7,500 ahead of where we would have been if we booked the same trip otherwise.
The corrollary to this is that we never would have booked this trip if we didn't have DVC points to cover the cost of lodging for us, so it's not like we are 'actually' $7,500 ahead (but then again, I do get another vacation with my family, which is priceless, so........).