The location is better than advertised. I honestly can't think of a better spot to stay. You might get slightly better views of more iconic landmarks, but they won't be this centrally located and accessible. There is no elevator and it is four VERY long flights of stairs. I had no issues getting in, the instructions were clear and accurate and the address was exactly right.
The apartment is not as big as the photos lead on, but it's not tiny. The guest bed/fold out couch is awful. If I rented this spot with another couple, I would be upset that one got the bedroom (where the bed and linens are great) and one got the living room, which was like sleeping on rocks. So I'd honestly say this place sleeps two or three people max, and that's if two of you share the bedroom.
We did have the smelly bathroom drain. It was pretty awful. There is no air conditioning and we had broken fans. It was unbearably hot and we ended up having to buy a fan just to get by. We slept with the windows open, there is a lot of street noise.
Overall, it's an amazing location and fairly clean, so it doesn't suck. But man, it is ridiculously hot in that place, be prepared.