Our experience was fairly okay. The flat is at 8 mn walking from Casa Da Musica Metro station (5 stations to the city center "aliados", change in Trinidade station, the airport is 40mn away with a direct metro line), and around 12 mn walking from bus stops that take to the city center but also the coastal part of the city.
The flat is small but sufficient to spend few nights in the city since you will spend most of the day outside exploring.
I would recommend the flat for 3 people if you are friends or a couple+1 but not if you are with family -except if no one minds sleeping on a sofa-bed-.
Just because in our case we were two daughthers with their dad, and you wouldn't let your dad sleep on a sofa so my sister ended up sleeping on the floor, which is not very comfortable as you may guess.
I would say 2 people would be more comfortable in there.
A part from that, there is a smell in the bathroom, not a big deal but it is there.
The host was there the first day, waited for my sister and dad who arrived later than expected and explained them the useful information.
And that's pretty much it!