I score this well on everything except communication. The apartment is extremely clean, as described, and in a convenient location. It's at the top of stairs, but this is clearly written in the description, so no surprise. It also had everything we needed to cook a little as well as being walking / metro distance to many many restaurants. There was lots of space it was comfortable.
The only issue is communication - Welkeys have another website through which you need to register your information, and they send messages there which means swapping between that and airbnb. Also I tried calling the phone number provided at one point, and received a recorded message that it only works during office hours. However there wasn't actually a problem, someone was there to meet us during check-in, and messages were responded to promptly, it was just a little inconvenient and not the usual experience for airbnb.