Do Marriott Rewards customers have priority reservations?

There is no evidence on Marriott's website that Rewards customers receive priority bookings. Along with other membership benefits, Rewards members at the Silver level and above do have priority reservation numbers and can take advantage of Marriott's Ultimate Reservation Guarantee.

Marriott provides the Ultimate Reservation Guarantee, wherein it pays for a member's hotel fee at a competitor if there was no availability at the chosen Marriott location. Platinum members are guaranteed a room with a 48-hour advance booking, but certain restrictions apply. Other tiered benefits include complimentary room upgrades, enhanced Internet service, priority late checkout and bonus membership points for completed stays.