I would like to know what company you work for that is able to negotiate a sweet deal like that with the major chains. They must be guaranteeing lots of nights per year and meeting and conference bookings as well to make that work. I work for a Big 4 accounting firm and we can't get a status deal with any of our preferred chains which include the four you mentioned.

Anyway, Marriott Platinum does offer the 48 hour room guarantee. That is the only benefit that makes it better than gold. IMHO, its a toss-up between Diamond levels at Hyatt and Hilton. I would go for the one that offers more properties where you will be traveling.

RIP