Luis always answered very quickly and was very nice and helpful. Patricia, his associate, welcomed us warmly. She gave us a few useful advices: where to eat and what to see from a native point of view, which was very welcomed.
The appartment is very well situated, less than 10min away from the metro station and 2 min away from Bairro Alto, the heart of Lisbon at night and can accomodate 6 people easily! The beds are very comfortable and the shower has a great capacity of hot water (no fear to run out of water when you stay with 5 people!)
One quick note: if you're going during the winter time, the appartment might be a little bit humid. There are electric heaters in every room (which is great!) but a warm sweater might still be useful. Also, there are a few ants wandering around in the kitchen, but the hosts seemed aware of it because a spray was available to help with that. We only had them the first day and after using the spray, they didn't come back for the rest of our stay (5 days) so no worries there either!

To sum it up: I recommand very warmly!
Thank you for making our stay in Lisbon so great!