I spent 16 days at this place while taking a Summer Program in Harvard and I am very satisfied. It is in the third floor of a private home owned by Joan, a very polite lady. You have your own private entrance, you almost forget that there is a family leaving downstarirs. The room is huge, with two sofa areas, a double bed (small for two persons but very comfortable for one), a microwave, a small fridge and a coffee maker. Full of natural daylight (it has a lot of windows and two lovely skylight windows). The bathroom is not completely private because you need to share it with the owner's business office during the day, but it gets completely private at night.
You can chose to have breakfast or not; I chose the latter because I usually have just a cup of coffee and some oat meal, which I prepared in the microwave. The shower temperature was perfect. I used a lot the AC unit because I was during the summer and the room was kind of hot if you don't turn it on.
Wi-Fi works perfect, it was one of my biggest worries because I needed to work with my e-mail during the night.
The neighbourghood is quite and beautiful. Althought I had a 20 minutes walk to Harvard Yard ever day, I enjoyed the walk a lot because all the area is beautiful, all the houses look like postcards. Some days I was too tired to walk so I just took a cab form Harvard, it's just $5.
The closest T station is Porter Sqaure, it's just a 10 minutes walk. You have restaurants and groceries stores on Massachussets Ave, just three blocks away.
The only con I see is that you need to climb up two stories through a steep staircase, so I would not recommend it to older people.