I booked hotels for my family for July in San Diego and Anaheim (across the street from Disneyland) for better than 1 penny per mile. So I am quite happy with Delta's Marketplace program and I now try to give Delta more of my business.
Inventory of the hotel rooms is limited, so it is not a good program for last-minute travelers. But since I almost never fly other than on a company-paid ticket, having an outlet for spending miles that does not involve flying is ideal, otherwise.