Solid experience at the Westin
I staid at the Westin for an event and had a great time there. It was all you can expect from a Westin: nice atmosphere, contemporary decor and good service. 
The rooms were huge and mine had a great view (23rd floor, overlooking the Charles and Cambridge). The bed was excellent as in any other Westin I've slept in. The bathroom was very spacious and confortable and everything was perfectly clean.
The whole hotel feels new; there's a nice bar at the lobby level and the property is connected to a series of malls in the Copley Place areas, which is very convenient in the winter. Location is great, just steps from Boylston and Newbury streets.
I'd definitely stay there again!