My wife and I stayed at Marylyn's apartment for about 1 week. Overall we had a good experience.
Location: Marylyn's apartment is only a few minutes walk to Nostrand Ave station where you can catch the A express and you are in downtown Manhattan in about 20mins. The area itself is safe, has plenty of supermarkets/delis/restaurants in walking distance but if you are looking for more trendy cafe's restaurants, this isn't the area.
Cleanliness: the bathroom is very clean. The room as well was clean when we arrived. We did have an issue with a strong smell of musk/mothballs that came about on the second day and didn't go so our clothes smelt of mothballs and it wasn't nice coming back to such a strong smell after being out all day. In saying this, when we advised Marylyn, she acted on it immediately and gave us a fan and a humidifier. It helped a bit, but not enough. PLEASE note that this smell is likely a one off and the host handled it as best as she could.
Space/Facilities: it is a quiet building and the host/s help as needed otherwise you don't see them. You share the bathroom with two other rooms and we never had to wait long to use it. The kitchen is small and basic which is fine when you don't plan to cook too much. Could do with more utensils such as tongs, wooden spoon and the spatula and the bottle opener need replacing.
The bed was comfortable and warm. There is plenty of hanging space for your clothes. The TV had very few channels (if that matters).
The check in and check out process went smoothly.