Timeshare User Group is the DISboards of the Marriott system.
I don't know the exact difference, but it's minimal. They are changing Marriott because of the merger with Vistana. If you just want Marriott properties without being limited to where/when/how long you can stay, then just grab resale POINTS off Redweek. There is a huge Marriott fee to transfer them to you, but they are virtually the same as direct.
If you are more flexible and want cheaper stays where you can get them, then a 2 bedroom lock off is the way to go. You split the lock off, deposit both units into interval and exchange both of them for a week somewhere. The studio side of a lock off with get you all of the Orlando inventory and you can use the 1 bedroom side for DVC, the Caribbean and Hawaii as long as you are flexible with when you go. The buy in cost for the deed that will let you exchange weeks will cost about $3000. The equivalent amount of points to get you 2 weeks somewhere will cost between $25,000 to $30,000 which is why I don't have any. Marriott deeds never expire though. If you buy a lock off, you can stay a week at SSR and OKW for about 40% cheaper than owning there resale.