Best feature is the location. The neighbourhood itself is very nice, and with lots of fun places to eat. It's easy to walk to downtown/the Public Garden as well.
I didn't take advantage of the amenities, so can't comment there. The wifi worked well.
Easy bus/train options nearby at Back Bay. Parking is difficult (street parking not possible for more than 2 hours Mon-Sat, practically no available spots on Sundays, although there are garages a short walk away). Depending on what you intend to do during your stay, you might be better off not bringing a car.
The bathroom situation might not appeal to everyone, but they are very upfront about that.
Bathrooms are regularly cleaned, and in good condition. In general the hotel is clean and well-maintained, and everyone is friendly.