THE GOOD: Nuria's apartment was very clean, and Nuria herself was a very responsive host who communicated quickly through the Airbnb app to answer questions as they arose. The location is certainly very central: right in the middle of the old city, an 8-minute walk from the main train station, and close to lots of public transportation. As others have noted, the rooftop terrace is, indeed, amazing. We ate breakfast up there every day, and took in the city sounds and lights up there at night. The flies and bees can get a little intense while you're eating, but to have outdoor space in the heart of an old city is really priceless.
NEEDS IMPROVEMENT: First, it needs to be said that Nuria's apartment does NOT correspond to what you see in the photos. Given the price--everything in Zurich is super expensive, and Nuria's place is no exception--what attracted us to the apartment originally when we found it on Airbnb was, precisely, its tasteful decor and attention to detail: the books on the shelves, the art on the walls, the choice selection of furniture (a dresser with a marble top in the bedroom, a yellow armchair in the living room) that looked simple, eclectic, uncluttered but comfortable. What we found when we arrived was virtually none of these things. Much of the furniture had been removed (no dresser in the bedroom, for example); some had been replaced with things that seemed just kind of thrown in there, like an afterthought, or like things someone was trying to get rid of from another home. Most of the art on the walls was gone, the books had been removed from some rooms and the rest were just jumbled onto shelves in the living room, the yellow armchair had been replaced by a rocking chair that was just kind of in the way... Everything was functional enough... it just wasn't at all what had been advertised in the Airbnb listing. Ideally, the apartment would be restored to its original condition; otherwise, I think the photos should be changed to reflect its current condition.
Second, the location: yes, it is central... but it's also important to realize that you are in the HEART of the most touristy part of Zurich. So it is VERY LOUD! In the summer, you really need to keep the windows open in the apartment at night to keep it cool. But those narrow, crowded streets are just inordinately loud: you hear everything, including the nearby church bells that ring every 15 minutes, 24/7, and the street cleaners that start to pass by around 5 am (we're early risers, but that's too early even for us). With the windows closed, it's less intense, but if it's been warm during the day, the apartment heats up and it's a bit uncomfortable to keep the windows closed at night, even with the (very welcome) Dyson fan in the bedroom.
The kitchen: just know that it's pretty bare-bones. We used it mainly for the fridge for breakfast items, to make coffee (there's only a tiny Nespresso machine; you have to buy pods; there's no other way to make coffee, no French press or stove-top espresso maker or anything like that, not even a drip cone...), and that's about it. I think it would be pretty tough to prepare an entire meal in there... it could be done, but updating and augmenting the supply of kitchen utensils would be useful.
Finally, in the front bedroom, the one facing the street, I'd say it's time to replace the mattress... or at least one of the two twin mattresses that comprise the "king size" bed. It's quite worn in, kind of sunken from the weight of human bodies over the years