We were very happy with Diogos apartment!
It's a sunny/bright and well equipped apartment, very central - close to Bairro Alto, the Tejo River, tram- and metro station.
The Check-In was very easy. We got a good describtion of the location and had no problems to find the flat. Check-In at 10:00pm was no problem. The neighboor gave us the keys and passed on her phone with Diogo on the line. He gave me some helpful tips.
The bathroom is small but renovated. My girlfriend was very happy with the hair-dryer (better than in the most hotels).
The kitchen has everything you need, toaster, water-boiler, nespresso-machine (with capsules!), stove, etc. And you can see the river from the kitchen.
It was perfect for a three day trip to Lisbon with my girlfriend. But it definitely would be not a problem to stay longer than only three days in the apartment.
It's an old house in the center of a big city - so it can be a little noisy in the nights (weekend). For me it was okay, otherwise you can use ear-plugs.