We stayed in the Residence Inn Waterfront twice in our recent trip to Maine since it is very convenient to the Portland airport. On the first leg of our trip, we had a room on the 5th floor overlooking the harbor. The room was beautiful and the view even better. We asked Barbara, the concierge, for dinner suggestions and she was wonderfully helpful, even letting us know that the hotel van could drop us off and pick us up. All of the staff at the hotel were very friendly and helpful. We highly recommend the hotel and will stay again. If your group is very rowdy, there are posted notices that there is a 10pm noise curfew and that the hotel will evict particulary noisy guests. I don't know what caused the notice but it is posted in the lobby and elevators.
We did not particularly like the breakfast buffet but noticed that many people were enjoying it so it may be our tastebuds. The hotel is within walking distance to the Old Port with it's shops and restaurants and we did not have any worries about being there after dark as has been noted in a few reviews.