While the interest rate at Disney is higher than other loans, it is an easy way to finance a
DVC purchase direct from them--even if it is only so that you can get started with your purchase as you seek out other and possibly lower rates.
But, when I was first deciding, I took my payments, my MF's, and my other Disney travel costs (airfare, tickets, food, etc). and compared it to what I was currently paying for our yearly trips to stay at the CR. Even with the Disney payments, I was still able to stay within my yearly vacation budget.
For me, it was about whether DVC was going to cost me MORE to own than what I was currently doing. Whether I paid it to them as finance charges on a loan, or for cash reservations through CRO, was immaterial for me. The bottom line was that I would not be paying more than I do now for my trips to Disney and at some point, when the loan was gone, I would be paying less.
So, I went for it and signed up. But I also looked into other options to see if I could get a lower rate somewhere else.
As it turned out, when I was able to get the entire thing covered on the Visa for 6 months, interest free, I didn't end up having to take out the other, lower cost loan and will have everything paid up in the fall.
As long as you have looked at your own situation and feel that you are financially able to handle things, think that DVC is right for you, and that you are happy with what it is costing you, then I say, go for it.
Good luck!!