Maybe it's a deal. I've followed the Embassy Suites rates for weeks. The Lake Buena Vista hotel seems to have a lot of unhappy customers. The latest thing they are doing is requiring every guests to wear an armband to "prove" they belong at breakfast, pool, etc. Truly bizarre in my opinion. I'm thinking they have lost a lot of business to other hotels. All the other Embassy suites in the area that don't require this. I've called.
If you decide not to priceline it, always check
AAA rates at Hilton properties. Those rates generally beat the listed "best available" every time.

Oh, and rates generally go down as your dates come closer, unless they are totally booked. I rebook with Hilton all the time to get a better rate. It's more advantageous for me to book with them than places like priceline. I use the points I get for free stays. (No points for priceline, on the other hand, if you don't need/probably won't use free stays, the rates are really good.)
One other thing--be sure to check the rates at each property-LBV, International Drive, Jamaican Court and Downtown. (Or whichever ones are closest to where you want to be.) I've found they are all different. Also check the specials listed at each hotel. Sometimes great deals are "hidden" in there.