I am in the process of closing my first contract... I debated on this for about a year or so. Finally I sat down with my dad, created some spreadsheets and did cost/savings analasys. It turned out this would be a saver for me. I already go to WDW 2 times a year and wish I could stay longer but the cost is what does me in. Just like this trip I could only afford to take a weekend and stay at a moderate on the AP rate. So for me this is definitely worth it and I doubt I will make it to WDW anymore than I already do.
I did do some costs of non DVC resorts too and if you plan to cruise all the time, it probably won't save you money, but if you plan to put $4K into a vacation and plan to do it every year, then I would guess based on my number we ran, it would probably save you money.
I think though, if I find I do wind up putting more into my trips than I used to, I would wind up selling my DVC and go back to paying rack rates. No way would I want to feel tied to something that no longer brings me joy.