All in all clean and well-presented. Stayed for two nights; check-in was easy and things were clear and fine to follow. Obviously it's not a hotel so nothing is provided in the way of soaps, water (except from the tap) etc, so make sure to bring your own.
The apartment is rather old and echoey, so it may seem like you've woken everyone up if you use the bathroom late at night, though showering is not permitted between 10pm and 6am.
It's a minor point, but the sofa in my room was a little stained and the shower in the bathroom also has the water go everywhere so you need to mop it after you're done.
All in all a clean, well-located (like 30 seconds from the Metro) apartment which is very affordable.