No it doesn't has any escrow feature yet. Every time you visit a link to a satoshibox uploaded file, it says somewhere on page :
"We are not responsible for uploaded content. Bitcoins goes directly to file uploader, we can't provide any refunds."
I think also it will be hard for the site owner to judge if the file was delivered as with promised features or not if you encountered with some problem where you downloaded the file not as expected or promised by the seller.
Is satoshibox is legit or not?
SatoshiBox acts as a platform for buyers to purchase products from sellers. AFAIK, SB hasn't scammed by taking money from buyers and pretending that no payment had gone through, but it doesn't mean that a seller might upload a blank .txt file and put it up for 1
BTC and label it as a "EZ money scheme".