There are
DVC members who have used the exchange options and loved every minute of it -- but Dean is right.
One thing prospective buyers should understand is that DVC membership does
not give you
full access to the 3,500 or so timeshares in the RCI system. DVC gives you access only to a small number of those, with varying degrees of difficulty exchanging (usually considerable difficulty), and a $95 fee for each reservation or change to a reservation. And even if you get the exchange, for most exchanges you are paying a premium rather than receiving a discount.
If you want to use a timeshare for exchanges, Dean, Brian and some of the other real timeshare experts on the DIS can give you some good suggestions.
Generally, I think the advice would be to buy only what DVC points you need
for DVC resorts and if you want to exchange buy some other timeshare which will give you full access to RCI or II at a fraction of the cost of DVC. Some of those timeshares (from fine companies) can be bought very inexpensively on eBay.