Marylyns apt is well located in Brooklyn, being about a 3 min walk to the Nostram subway station. Easy connections and direct routes into Manhattan and to both JFK and La Guardia.
The apartment we had was on the 3rd floor, so it did require a few trips up and down the stairs, which really is no problem if you're in shape.
The bathroom is shared, but it never became an issue for us, as there didn't seem to be many other guests in the building. There is 1 per floor, so even if it would have been occupied, (which it never was) you could always go to the next floor. It was also very clean, and there was good water pressure, and plenty of hot water.
The room itself was warm (weather when we in NYC was very chilly). The bed was firm and comfortable. There was also a couch that folded into a bed. There was enough room for 2 people to cohabit comfortably. Though we never really cooked, there was basic kitchen amenities to prepare a simple meal should you choose.
The fridge seemed fairly new and worked well, and we did toast bagels for breakfast.
The street that the apt is on is very quiet. Having stayed in Manhattan on previous trips, you realize how traffic/honking sirens go on all night and can be very disturbing. Not at Marylyns.
The main street (Fulton) has lots of shops and services, including grocery stores, and a lot of fast food outlets. It is a little sketchy at night, but we never really felt unsafe, as there always seemed to be a lot of people around.