More general Churn Board info, but UR transfers to Marriott so still applicable.
SPG and Marriott have killed it with their merger. SPG transfers 3:1 to Marriott and will match status. Amex Plat. just got a buff and now includes Hilton Gold, SPG Gold, Marriott Gold and Ritz Gold.
Marriott's most advantageous redemptions is their travel packages. Smallest denomination offered is 200k Marriott points for a 7-night Cat. 1-5 certificate and 55,000 airline miles. The most efficient is the 270k Marriott for 7-night Cat. 1-5 and 120,000 airline miles. Marriott Personal, Business and CSR sum to 280k Marriott points. If you redeem the 120,000 miles on AA, it's enough, with some spare, to RT 2 to Europe and 7 nights of hotels.