Have you tried Andaz Ottawa? Not that Westin Ottawa is a bad hotel (far from it), but in my humble opinion before being considered among the best Westin in the world, it would first have to compete better in its hotel category within its city. Andaz Ottawa is better in almost every way: odds of suite upgrades, breakfast, quality of the room, elevators that work like normal elevators, hotel bar, price, etc.

Not to say that Sheraton Ottawa > Westin Ottawa, but I would dare to say (as shocking as it might sound) that one could have arguments for why the Westin is not even the best value proposition within Starwood in Ottawa, but that it's rather the aging Sheraton that is, instead.