Perfect: 10/10.
The apartment was stylish, not overloaded or overdecorated; clean and exactly to the pictures on the internet. Newly renovated with love for details and history, like the wooden floor in the bathroom or the old stone walls. There was everything in the apartment one needs. Size: for 2 people enough place. And everything we asked for ( like more hangers for clothes, iron, etc.) has been delivered quick and friendly. The landlord was punctual, reliable and friendly. There have even been welcome drinks in the fridge, amenities in the bathroom, ... journals (economist, time magazine, newsweek). There is even an air-condition, which is quiet and powerful. It's only one room (beside bathroom of course) but the layout of the flat is smart, the kitchen is behind a "wall/wardrobe", so you have the impression of separate rooms. We did not miss a thing.

There was not much traffic in the street, thus it was not noisy (the noisiest thing are the sea gulls, but in fact they can be quite loud ;-). Wifi was okay.

The street itself has seen better days, but within 5 minutes walk you are in Via Catarina, a pedestrian area with shops and bakeries/cafés (my favorite "MENGOS", excellent (!) coffee, very good bakery, cheap and typical portuguese) or the very famous Cafe Majestic. For your daily shoppings there is a Pingo Doce supermarket about 300 m away.
Depending what you want to visit, the area might be a bit long (15 - 20 min) and steep) way to walk from e.g. ribeira or university area, but via catarina is definitely one of the city centers. I can recommend this apartment absolutely.
There seem to be different types of apartments in the same house, I have seen one with garden and barbecue. Check with the landlord, if available.