Our stay in Gonzalo's Guesthouse was perfect. It is really well situated: in a street with cafes and restaurants around but without any noise issues. When you step out, you're right at the bottom of beautiful Alfama.
The apartment itself was very comfortable; nice living room, comfortable beds, overall very clean. The little balcony is facing the south; perfect for your morning coffee or afternoon drinks in the sun. The shutters keep the heat out during the day.
Gonzalo gave very clear check-in/out instructions and description to get to the apartment.