DVC's lowest rate is 9.75% (with 20% down, monthly payments via direct debit and 10-year loan.)
One topic you'll want to investigate is whether the interest is tax-deductible if you go through another organization. If you finance through DVC the note is considered "secured debt" and interest is normally under the "second home" provisions of the tax code. Interest on a home equity line should also be deductible.
If you were to use a credit card or signature loan to finance, interest is not deductible. I don't know how the loans that Tammac issues would be classified.