For business travel, Marriott seems to do better in the US than any other brand. All mid-size and larger cities have a FS Marriott and you can always find a Courtyard or Fairfield Inn in small cities. I like how every single FS Marriott has a lounge and the service / facilities are very consistent.
I've been SPG Plat and Marriott Plat for multiple years and I always rely on Marriott for business travel. If I paid for more leisure travel, I would lean SPG as the perks are better.