Sergio's apartment is clean and modern. It was fully stocked with just about everything you need, and Sergio was extremely fast and responsive if we had any questions. We were extremely comfortable here.
The location is also good. Lisbon is a large and hilly city, so walking to all the locations from any one point will be difficult, but the apartment was within walking distance of many the best neighborhoods. It was also within walking distance of train stops, but again, due to hilly nature of the city, most walks will be tiring. The neighborhood was also very safe. Would recommend staying here.