Maria's place is extremely well situated in the heart of Lisbon, walking distance to multiple metro/train stations yet mostly quiet (you may want to keep a fan on to avoid hearing the odd 3 am group of people walking up the street ;)).
From this unit you can walk to the mercado for groceries, less than 1 km to the waterfront and to a ton of restaurants and shops.
The unit itself is spacious by European standards - we were five adults.
Maria, Szilvi and Patricia are outstanding hosts; swiftly answering our questions beforehand and readily available to help during our stay. I highly recommend this unit.