Nottingham Nick:
Yes, I believe its on the red line at the Bayside Expo Center stop.
I reluctantly stayed at the Back Bay Hilton after I reading several poor reviews on here. But that was before their renovation, and thought I'd give them the benefit of the doubt.
I'd give them a thumbs up. From what I've read on here there was a gold/diamond check in area that was unmanned. This seems to have been turned into a gift shop.
No Exec Floor but they give you Bounce Back weekend certs for breakfast in the restaurant. Due to a short wait, we asked if we could trade them in for coffee and danish in the lobby; and you can.
As for upgrades: The hotel is basically triagular shaped, with one corner on each floor providing space for two larger rooms with panoramic windows. It gave us a very dramatic view of the south shore. The room had no bathtub, but more interestingly, a double headed shower. A worthwhile trade off. Fitness Facilities met our needs too.