If you're considering this apartment, book it! We stayed here mid September for 5 nights and had the best time! Both my wife and I arrived back with Lisbon firmly planted as our favourite European city and that was in no small part down to this great apartment.
It's situated in a superb neighbourhood packed full places to eat, drink and catch a view worthy of any guide book and it's only short (downhill) walk to everything else that Lisbon has to offer.
The apartment is a great space, beautifully light and airy and very stylishly decorated - the hosts have taken their time to make the most of this great space - a true home from home! It's very clean and has everything you need to while you're staying in Lisbon.
We'd definitely return!