Seth, I have had ZERO luck with SFX and deposited a Wyndham Kona Village 2 bedroom for July 4th week for 2008. They cannot, or will not, give me anything much at all for that deposit. I requested Maui and Kauai a couple of different times, and I wasn't asking for specific dates, and I wasn't asking for prime season at all.
I am very disappointed with SFX and would not recommend them, even though I have a platinum membership.