For those that don't know how certificates work.
Seven night and five night certificates1. Marriott certificates can be used for any reservation that can be booked with points. To search for reward availability simply go to marriott.com and check the box to search "using points".
Marriott hotels are divided into categories. (Cheapest being category one) below is a list of all the category 1-5 hotels
http://www.marriott.com/hotel-search/Category1.hotels.Category2.Category3.Category4.Category5/ 2. A 5/7 night certificates must be used for 5/7 consecutive nights. The reservation cannot be split up.
3. In order to hold the room you need a credit card. Your card will be kept for incidentals and you won't be charged for the room.
4. Certificates can be gifted and the room can be booked with anyone's name as the primary guest (and not just secondary guest)
5. Gold or plat benefits depend heavily on the hotel. At check in you may or may not get an upgrade.