I think every property, of any brand, that I've looked at carefully on Marriott.com during the past year, shows "Laundry" under "Featured Amenities On-Site." Unfortunately, it's meaningless. In some cases, it means a self-service laundry room. In other cases, it means there's a plastic bag and a multi-part laundry form in each room.
A few years ago, we vacationed in Pacific Northwest. A photo on the website of the Residence Inn Portland Downtown/Pearl District showed a laundry room with plenty of machines and big picture window. Although we could have stayed in other good Marriott properties in Portland, the decision was easy. We stayed at the Residence Inn for five nights in the middle of our trip. We did laundry when we arrived and before we left, giving us clean clothes for our entire trip. Nobody ruined our clothes. It didn't cost $5 to wash each piece of underwear.