This review is primarily for less experienced travelers with a focus on Americans.
Location - I've been in several European AirBnb rentals. Never been to Zurich and selected this place somewhat randomly on purpose. Wow. If you want to be in the middle of the action on all fronts (museums, shops, cafes, restaurants, etc.) this place is incredible! I was there for nearly 3 weeks and just exploring the immediate neighborhood took that long. Loved Niederdorfstrasse, many excellent coffee establishments as well (though Cafe Noir is my favorite). It's right next to Urania parking, the river for running and the main station.
Apartment - I come to live like a European again and this building/apartment has all the wonderful quirky qualities that make it such an enjoyable experience. Neighbors were very nice. I had read about noise, well if you close the windows there isn't that much from the eating establishments below and frankly it's almost like white noise. Floors are creaky so if you are more than one, the person who gets up most in the night should be closest to kitchen/bathroom (I figured out stepping on the edges in the hall eliminates almost 100% of the squeaks, as I did early morning solo runs and didn't want to wake up the light sleeper). Beds were fantastic (both of agreed on that) I have never slept so well. Hot water is instant, wish I had that at home.
Trash Disposal - This is a little bit my fault, in the U.S. we are used to huge trash areas in apartment complexes (not in public venues) and the disposal rules (in many areas) are not too complicated. I panicked a little reading about it in Zurich (police checking garbage, fines, etc.), so just a little bit more clarity would have helped. There are numerous trash "cans" in front of the church to the right but Americans are trained to recognize those as just public cans, not for homeowners/renters. Well, some are marked specifically for trash which must be in special bags (provided by host) and you have to be careful not to include PET bottles, things made of metal and cardboard.
Host - Nuria communicates well and is very nice. She (or someone else) actually came to drop off some extra supplies but my fellow traveler couldn't work the intercom system, so it was put in front of our door. We didn't use most of the supplies at all (I hand wash stuff) and tend to drink coffee at cafes when abroad but it was very much appreciated.
Some Observations (using an American perspective) - Very open building, shoes and other family effects are outside the door of many apartments. Elevator goes to 0, 2 and 4th floor and fits one person with luggage, fun! Flat stays warm even with windows open (radiant heat from other units?) and it's 40-50 F outside. Be sure to keep bathrooms windows open to let everything dry and squeegee the glass shower door after every use (learned that in Norway).
Summary - Delightful experience, highly recommended if you want to be centrally located to everything and it was nice to have an elevator that went up 2/3 of the way especially when hauling heavy luggage! Price was very reasonable, when a Swiss I befriended asked about it he was quite surprised.