Great place and location
Hi;
I have to warn I tend to stay far away from chain hotels like Marriott or Hilton and prefer boutique hotels as a rule. So, if you like "big brand" hotels, I might be biased in my views. 
Back Bay Hotel is located in an excellent location. You can walk to everything, parks, tour stop, restaurants and lounges. The hotel used to be a police station; so it has some charm because the building was done with some class, and the renovations are good. 
The bar downstairs is decent and so is the lounge up the street called Tico. 
Only thing I would suggest is to get a cable for the internet when you check in as the Wifi is flooded with interference form the buildings all around.