All Marriott owners can book stays at 5 x Ritz properties.
However, the points needed/nights are higher.
The
5 Ritz Properties [in order of availability]
- San Francisco [Most Available]
- Vail
- St. Thomas
- Tahoe
- Aspen [Most Rare]
Strangely points needed for the Ritz in SFO is a better deal than booking at the Marriott Pulse SFO.
Ritz Availability
Depending on the MVC Elite level it can be difficult or easier.
Higher elite level owners [Presidents/Chairman's-Club] can book 13-Months prior without restrictions.
Vistana
St/ Regis & Westin are Vistana hotels with the exception of a few Westin's that are also resorts.
With the Marriott buyout of Starwood, the 2 programs are now merged, however, this only relates to hotels [Not-TS].
The Marriott Vistana merger with Vistana [due to the purchase of ILG which owns Vistana] should be closing shortly [delayed due to COVID].