I've ridden public transit in Ottawa, Vancouver & Toronto, and never got the impression it was dirty. Colourful sometimes, but not dirty.
I've said elsewhere that when I lived in Toronto and had a car, I took the streetcar during the week & only used my car on weekends. The stops were close to my destinations on both ends & I liked being able to read or watch the world go by. Plus, getting parking downtown was a hassle.