I absolutely loved the apartment! It was clean and neat and good standard (newly refurbished). It's sunny and with a nice view. I was met by Carlos&Rui's sweet friend Nöelle who had also bought some food supplies and wine, and there was even the traditional Portuguese Ginja and Portwine -a nice treat :) The food supplies was a lifesaver when arriving with a tired kid! The apartment is a short walk away from Graca and close to the metro station, only two stops away from Rossio/downtown (also within walking distance). A supermarket (Lidl) is just across the road and there are plenty of restaurants nearby. I got to meet Carlos&Rui on my last day/check out, they were really nice and outgoing guys and were even sweet enough to drive us to the airport. We had some contact on messages and sms before and during the stay, they were easy to reach and responded quickly.
I would rent the apartment again and I can highly recommend it!