I stayed for five nights. I never met Joao or Marta in person but they were very responsive to any problems. The apartment is lovely and the kitchen is amazingly well stocked with pots and pans, cutlery, pretty much anything you would need. Check the stock of condiments before buying anything as well. The apartment is very roomy and light. I like the European shutters that rise up and down. There is a bathtub with a nice shower as well. Small supermarket is about a 3 minute walk. Junoon restaurant, when it is open, in the next building ground floor has a decent 5 euro menu, for a quick meal.
The apartment is on the first floor above the ground floor, and a restauran/bart on the ground floor has a TV outdoors in their patio, so there is a bit of noise--just a murmur really--and some airplane noise, but nothing that really disturbs one. I thought the apartment might be hot at the end of August, without aircon, but leaving the shades mostly down during the day kept it cool, and opening windows in the early evening quickly cooled things down very comfortably. The nights, outside, were quite cool actually.
I used the metro to get to centro. The apartment is about a 10 min walk to the Cidade Universitaria station. Ride to Campo Grande and change to the Green line, and it is a straight shot to centro and all the popular districts. BTW on the ticket machine there is a small British flag icon at the bottom left of the screen to change the language to English; someone had to point this out to be, making my life a lot simpler.