Sheratons tend to be old and shabby. Toiletries are of cheap quality to the point where I bring my own. I tried to avoid Sheratons when I can. They have Executive Lounges, while the Westins do not.

Westins are a step up, and are typically newer and sharper looking. All Westin properties are known for large gyms with lots of fitness equipment.

That's how I see it, anyway.