In the U.S., I used to seek out Westins, but they seem to have expanded a lot (e.g., the Washington, DC metro area, which has several nondescript ones) and watered down the brand. I find the brand identity weak. For example, they used to have the "Heavenly Bed" before every chain upgraded their beds, and "Heavenly Bath" with really nice toiletries and high water pressure. They still market the Bed, though it's less of a differentiator now than ten years ago, and they seemed to have dropped the Bath marketing.

Internationally is different; I have stayed in a handful of Westins in the Middle East, Asia, and Europe and they have been at a very high-level. Though Sheratons can be much better outside the U.S., too, Westins are almost always a step up.