I don't know for sure, but the consensus around these boards seems to be that Marriott is the stingiest of the bunch when it comes to competitive status matching.

Just as an aside, I used to be pretty happy as a Westin Premier Burgundy member. I was also Sheraton gold but found it virtually worthless. So what does Starwood do? Combine the programs, make people like me who were mid-tier in both mid-tier in the new one, but give the benefits and treatment of the Sheraton level! They have now become my FOURTH tier, below Marriott, Hilton, and Hyatt.

My biggest problem with Hilton is inconsistency, even at the same property. One time I'll check in and get a warm welcome and a suite upgrade, the next they'll act like I'm a vagrant and they're doing me a favor by letting me pay for a room with the wrong bed and smoking preferences.

Good luck if you switch to Marriott. There are pros and cons to all the programs, but over time I have found Marriott to have the highest consistent level of product and customer service quality. I hope they show the same standards for you!