We own DVC with 4 families - my parents and two siblings are the other owners. Four of us are on the deed. We all get full membership benefits and most mailings. We bought 220 points 12 years ago - 55 points per year per family. This is enough to get a studio S - F most of the year, or more if traveling every other year or pooling points. I'm sure this sounds like almost no points to most on these boards, but we have all had great vacations, including once sharing a grand villa. The cost for each of us to buy a full membership would have been prohibitive for us. We don't all go together every year - in fact, we usually go separately, due to work and school schedules.
A few years ago, my brother and I each bought a small (55 point) add-on. I did this so we could stay in 1 bedroom units, as our kids are getting older and the space makes for a better vacation. Whereas we used to go every year for 5 nights (and usually added a few cash nights) we now go every other year and include one or two weekend nights on points. The flexibility of DVC works for us.
I think this works for us because we are all related and most of the time we all get along. Keeping track of point usage and banking deadlines has mostly fallen to me, but I use e-mail to keep everyone on track. The math involved occasionally makes me pull out my hair, but it all works out in the end. I would not advise this plan for people who are not related or who do not communicate well with one another.