The host Pedro was great and very helpful. He gave us some useful tips about Lisbon, where to go, what to see, how to get there etc.
The appartment is just about big enough for 2, but it's nice and cosy and, more importantly, situated in the city center (+ the tram is really close, about 50-100m). It would be quite hard to find though, had Pedro not picked us up at the train station (it's in a small alley).
All in all we were happy with the place.