Loved Parts of It, Disliked Parts of It
First off lets start with the location - it could not be better. Just off Copley Plaza the Westin Copley has an ideal central location. It's great for both business and leisure.
When we arrived it was late on a Friday night. When we pulled up to the hotel we could not find a valet and there was a massive crowd in front of the hotel. After getting out and searching for the valet we finally found him. He was most apologetic and nice once we found him. He apologized that the hotel had booked two large college events that night and they were grossly understaffed. When we entered the hotel we had to walk through a sea of blue smoke as at least 30 to 40 people were out front smoking. It's really gross to have to walk through this to get into a hotel and it's actually something the hotel can control. Ask the smokers to step to the sides and do their nasty and not force arriving guests to walk through the haze.
When we arrived the lobby the parties were letting out and the first thing we saw was a very drunk young girl puking on the floor. 
We were traveling with two teenager and two adults and had two connecting rooms. I called that day to make sure that we had one king bedded room and one double room - connecting. I was assured that we were all set and this would be the room arrangement. However when we arrived we had connecting room, but both kings! So after a lot of juggling and movement the front desk clerk found us one king, one double on the same floor, but NOT connecting. The hotel screwed up - but I will say that the front desk clerk was helpful, patient and friendly with the mistake and worked his best to correct the situation. This was the best he could do and I really felt he cared about the screw up and was working hard to fix it.
We loved our rooms. We both had great views. The kids looked over the river to Cambridge. Our view was of Boston. The rooms were comfortable and both were a good size. You can't beat Westin for the most comfortable beds on the planet. We were very happy with our rooms and the comfort factor of the hotel.
We ordered room service and one tip - get the clam chowder it's as good as any in Boston. The food was good. Room service was fast and friendly. However on Friday night we put our dirty dishes in the hallway and they were not picked up by the time we left late Sunday morning. The dishes sat out in the hall the entire weekend.
Overall the service was good. Lots of little mistakes, but always friendly and I did get the impression that the staff cared and were interested in making things right. I loved the location and loved the comfort of the room. Maybe we just hit it on a bad weekend. I would certainly give it a second try.