We got a great rate through airbnb, however, what we paid should be their regular rate for the room we got (Deluxe King). Our bed was hard, we expected a cushier (is that a word? Lol) bed, the pillows were ALL soft, no option for a firm pillow...and stacking themdidnt help. My neck and back are sore. The shower had crummy pressure and you had to turn the dial 3/4 just to get it hot enough to enjoy your shower.
I can say, it was clean and an overall pleasant stay. Great location. Your definitely paying for the name and location though.
If you don't have high expectations and want to pay almost $400 a night for the kind of room we got (without a great deal) then by all means, stay here. It is safe, the place is beautiful, and the staff are friendly and helpful. They could definitely upgrade a few things so that they'd live up to the Park Plaza name.
We are planning on staying somewhere else next time we visit Boston.