Hotel Adler is in the Old Town of Zürich, walking distance from the train station, art museum and big churches. The location was perfect.
If your room faces the street, know that weekend nights will be loud. The window had a single pane and didn't block the noise. On top of that, the walls in this hotel were so thin that I could hear snoring next door.
The staff was friendly and helpful. The hotel offers a 50 percent discount on the art museum and had umbrellas to borrow.
My room was clean and tidy, and also compact, with a single bed. It's nice to have that option as a solo traveler.
I appreciated that the hand soap and shower gel/shampoo were in reusable containers but wished that the conditioner and lotion were, too, to save plastic. On the same note, bottled water seems unnecessary in a city with drinkable tap water.
Overall, Adler was a comfortable hotel, but if I returned, I would ask for a room facing the courtyard (and bring earplugs regardless).