Never mind guys here trying to wind you up, the price is good if the mileage isnt too high.
I am contemplating this too, and I am not convinced that the Escape engine is worth the extra. I know that the swap will be easier, but in your case your saving $650 and that will pay for your quaife Limited slip differential (LSD) that you will need to keep your power on the ground.
What miles are on the Taurus engine? Remember that even though the Escape engine is the most straight forward swap, there are plenty of guys on here who are using 3L Taurus engines who will be able to help out.