I and my friends were very happy with our accommodations and Hermina's place. We stayed in the attic room (C). (The house has several other nicer bedrooms that may be available - lots of options for different size groups.)
Room C, as advertised, was minimalist but it was a big open space and had plenty of room for the three of us to sleep and spread out our stuff (slanted ceilings so not a lot of head room for the large amount of floor room). The staircase to the room is very steep and the bathroom is one floor below so don't stay in this room if you would have a problem with those things. There are also only a few outlets in the room so don't plan to plug in a lot of electronics.
The kitchen, dining room and living room are very nice and the bathrooms are clean and functional.
The neighborhood was okay with a few bars and restaurants, a grocery store, liquor store and other shopping. We picked up groceries and made breakfast each day. The kitchen is well appointed and well organized. The only problem with the neighborhood is that there are usually people hanging out in the area of the shopping center. If you find this type of environment uncomfortable you may not be entirely happy with the neighborhood but we did not have any trouble with anyone other than minor annoyance from a pan-handler. Note that the house is next to the police station so it is in a very safe place.
The subway station is just a few blocks walk from the house - less than a 5 minute walk. Public transport is the way to go in Boston - you can get a 7 day pass for $19 that gives you unlimited use that even includes the inner harbor ferry. I found this subway stop just as convenient for my needs as when I have stayed near the Back Bay stop - yes I had to plan additional time but it was just as easy to get to all the places I visited.
If you will be driving to Boston for your visit you will be happy to hear parking is simple near Hermina's place. Street cleaning rules only make you move your car once every two weeks so it should be easy to arrive, park and not worry about your car until you need it.

I will most definitely stay at Hermina's place for future trips to Boston. Most likely I will stay in one of the other rooms but I was very happy with my stay in Room C for this visit.