[on the location] Solo female travelers may want to avoid this place. It seems to be at the very center of where men in Zurich go to find female prostitutes. I am a fairly frumpy 36 year old, and I was constantly solicited by men while simply trying to go out and buy food or make my way to the apartment. Because the entrance to the apartment building is on a poorly lit side street, the situation feels a little dodgy. To be clear, every man who solicited me was quite polite and took 'no' for an answer, so it was very Swiss and above-board in its way, BUT I found it to be a hassle that's not worth it. This does not reflect on Sevi at all! If I had a traveling companion or I were a man, I wouldn't mind the location.
[on everything else] Everything else about this place is fantastic. Convenient to the downtown. Good price. Sevi is an exceptionally thoughtful host who puts labels up and makes things very easy to use. I also found him very flexible re: check in and check out. And he's a nice person to talk to either about Zurich or about other things.