I wasn't sure where to stay in Prague but U Stare Pani was eventually an amazing choice. The room was very spacious and had AC, a beautiful view over a courtyard with classic orange roofs, and was always quiet whatever the noise from the street side.
The buffet breakfast was simple yet diverse, and I especially liked the professional-grade coffee machine. Staff was very servicable and got my clothes to the laundry once (expect around 8 euros for a full bag).
I didn't recall Prague being such a small city but almost every attraction was nearby. The hotel is basically located in the heart of the old town. There is even a bicycle rental shop just under the arch you can see when stepping outside.
The restaurant was only open to group reservations, but some amazing dining places like Café Louvre (my favorite restaurant), Lehka Hlava (rare vegan) and La crème de la crème (most popular ice-cream shop?) were only 5 minutes on foot.
I will definitely stay there again next time, since it wasn't more expensive than other places while I'm sure I can have relaxing nights thanks to the quietness (ask for a courtyard room if it matters for you) and the AC.