My wife and I stayed for 4 nights at Graça's courtyard in October. We were given a warm welcome (and a bottle of wine!) on arrival, a quick guide to the flat and directions to the nearest bakeries and supermarkets just a short walk away. The flat was perfect for our needs - plenty of living space, comfortable bed, air conditioning, excellent wi-fi and a nice little kitchen stocked with all the crockery you would need for a few days. We didn't make use of the courtyard very much as we were out for most of the day, but it was nice to have a bit of private outdoor space connected to the flat.
The Graça area is a quiet residential neighbourhood so a quiet night's sleep is guaranteed. Graça is a good base from which to explore central Lisbon, particularly the areas of Alfama and Baixa. But do note that Graça is at the top of the hill, making it an easy walk downhill at the start of the day, but a little more tiring when heading home. That said, the tram no.28 stops on the main street of Graça and there are plenty of taxis around giving you easier options to get home. There is even a bus stop outside the apartment building - you can get the 712 bus from here to Alcantara Mar.
Overall we would recommend this apartment as a clean, inexpensive and convenient base from which to explore Lisbon. Thank you Teresa and Candida for making our stay in Lisbon an enjoyable one!