1.) I like Marriott mainly because of their beds. The beds are always the same: firm. A firm bed is the very best choice for the back. I never had a soft bed at a Marriott property.
2.) I'm very confident with the bright light in the room - especially in the bath room.

I found 1.) and 2.) to be very consistent. My experiences come form European Marriotts (Germany, Austria, Netherlands, GB, ...) so far. So long Marriott will keep their excellent beds and their bright lights, I am going to stay there.