I still maintain that for the average out-of-state occasional visitor to Boston, the place to be is in Boston proper, not Cambridge. If one had a week in town, or visited every year or so, that's a totally different story. Cambridge has much to offer.
But, again, for someone asking for assistance in determining the key hotel to select for a short getaway trip to BOS, I can't imagine recommending anything above hotels (of any brand) in the Copley area. For Starwood, this includes both the Sheraton and the Westin. Marriott also runs a great hotel adjacent to these two.