New management and changes are not so positive
I have stayed religiously at the Watertown for a LONG time, probably 20 visits or more in total. My brother lives nearby and I am from Boston, so I stay here on all my family visits. The hotel was a hidden gem, as other reviewers say. Small, cozy, clean, modern, organized, simple but tasteful, quiet, and a good location. 
It has changed. I just arrived last night, and noticed two main changes: 1) Instead of Aveda soap products, they now have Tommy Banana dispensers (feels more like a Sheraton or Hyatt or Hotel 8), and 2) the free breakfast area is now a pay-as-you-go cafe (which few use because of this).
Lastly, they have not updated the furniture or carpets with the merger. So, what you get is a hotel that is starting to fray a little around the edges (it was about time for some cosmetic upgrades anyway) too.
Also, because I used to stay so often, I could get the best room for a very reasonable rate. That seems to have changed now that they have been bought/merged. 
This is still a good hotel (average to slightly above average). It still has some of the feel and flavor of the old "Watertown". But it has changed.
I would probably come back, out of convenience. But I would also look around more in the area and over in Wallingford and Freemont. I would look at B & B options, and other options in the same price range and comparison shop. Before, I wouldn't think twice about coming to the Watertown.