I stayed for a month while rotating at Beth Israel Deaconess Medical Center. This was my first Airbnb experience, and it was wonderful.
The room: size of a normal bedroom. I had the smallest in the house and it's the same size as my bedroom growing up. There is a dresser, desk, nightstand, closet, and two large windows. Don't feel the need to pay extra for the big bedroom because you'll be comfortable in any of the three rooms. I spent many afternoons just lying in the queen-sized bed feeling at home.
There is no AC in the house, but there is a ceiling fan and windows with good breeze in the bedroom. I was in Boston during July, and temperatures approached 100 F, but it was manageable with sleeping with minimum clothing and keeping the fan on.
The rest of the house includes a kitchen with adequate counter space and a large pantry, a quiet living room, and a washer and dryer. Washer is free but dryer is $1 per load. Detergent is provided. There is an indoor drying rack in case you want to dry your clothing for free. You will share one bathroom with the other guests, but I don't recall experiencing any hassle and I really felt like I was the only one using the bathroom at times since there was never a wait time.
The hostess: Michelle will make you feel like you've known her for years. She has a remarkable capacity for empathy and is able to see your worldview despite not living in your shoes. Very fun to talk to. Extremely helpful and will go out of her way to make sure you're not burdened. She is not overbearing and gives you your space. I had two dinners with her and a couple of guests/housemates, she likes to make a little dinner or something similar before each guest leaves. I felt like I was with a friend when I was with her.
I highly recommend staying here. Michelle is an honest host and a good example of some of the good you'll find out in the wild.