Hugo's apartment is right in the heart of Principe Real with a short walk to the lovely park, many excellent restaurants and bars and most importantly as I have discovered, Neva Gelado.
The apartment is the perfect size for one or two people. The bedroom is well placed in the back of the apartment so the street noise that manages to make it through the double paned windows (the apartment is on top of a very popular pizzeria and next door to a restaurant, both with outdoor seating) does not manage to make it into the bedroom. A quiet sleep was important and the only time I had issues was sometime the pizza employees made a lot of noise in the center lightwell area or neighbors have their windows open because they apparently don't have air con. I stayed at the apartment over a month and was bothered by noise maybe only once or twice.
I worked remotely during my time there and there is a very comfy desk with a nearby outlet and wifi was always working and strong.
Maria, who met me and showed me around, is wonderful and if you're there for more than a week, she will come and clean the apartment and change sheets and towels.
My only little nit that is not Hugo's fault is that the common area stairwell did smell of sewer from time to time. If you're ultra sensitive to smells you may have an issue but I did not find that it came into the apartment.
The neighborhood is well-placed to easily reach all the neighborhoods you will wish to see. Would definitely stay here again.