I stayed in Nuria's apartment in August 2012 for two days. I highly recommend this place. The location, in the Altstadt, is very central. It's a 10-minute walk from the Hauptbahnhof and the city, and also a short tram ride to the lake where you can swim. The apartment itself is full of charm and very clean and comfortable. Nuria's apartment building has a lovely terrace on top, where you can sit and read, or eat a meal. Nuria is very friendly and answers all your questions quickly. If I'm in Zurich again I will definitely try and stay here.