I have stayed at the Best Western Pioneer Square Hotel recently, as that is where our company put us up on a recent trip to Seattle. It was located near the conference rooms, as well as close to many other areas you may want to see.
The hotel itself is really nice. The rooms are very comfortable, and they come with the little extras, like the ironing board and coffee pot in every room. I loved the decorating, which went with the historic area of Seattle where the hotel is located.
As I'm not from Seattle, I would read the answers from those folks who are, about the safety issues. My co-workers and I did not experience any problems at all, and we had quite an exciting experience, even though we were there to work.