Perfect
I have stayed at the Westin Copley Place three times, and have not been let down.
Location: excellent location, close to Prudential Center, Back Bay, Newberry Street (fine shopping and restaurants), the T. The mall is connected to the hotel, and has just about every store imaginable, and if it doesn't, Newberry Street is 2 blocks away.
The Hotel: the rooms were decent sized with a large bathroom. Our room over-looked the Charles River. Westin has the oh so comfy Heavenly Bed, and a great shower head.
Front desk staff is friendly and knowlegeable about the area.
Cons: Parking, close to forty bucks a day, but that's mandated by Boston, not the hotel. It is the standard charge for any public parking.
The only other potential problem that some may have is that Westin Hotels are now smoke free.