Great Overnight Stay
Stayed here for one night in late July. We declined an offer for a discounted junior suite upgrade, and we didn't regret the decision. The Kenmore room was nicely decorated and cozy, with a desk, oversized sitting chair, and large king-size bed. Both the room and bathroom were impeccably clean, and the bed sheets were very comfortable. The hotel itself is in an extremely convenient location, yards away from the nearest T station and just a short walk from Fenway Park, Newbury Street, and the Prudential Center. There are dozens of restaurants in the area, and if you're only staying for one night, it can be a challenge to decide which ones to try. 
The hotel staff was always welcoming and attentive. The valet Nick seemed like a great guy, and everyone at the entrance was friendly and ready to assist us with luggage. It rained the night we were there, and the doormen were actively hailing cabs for other guests. To save time, we ordered room service breakfast on the day we checked out. On the form, we indicated a time of service between 10:00 and 10:15, and there was a knock on our door at exactly 10:02. We ordered french toast, eggs, and coffee, and the food was exactly what you'd expect from such a nice hotel. 
In summary, we'd highly recommend the Hotel Commonwealth. It is a beautiful and convenient place to stay, with luxurious, bright, and clean rooms. It would be a difficult challenge for one to identify any significant fault with this establishment.