We spent a whole month at Manuel's place, and were overall very pleased.
First, we actually arrived in Lisbon with a different reservation. That rental was not as advertised, so luckily AirBnb let us change, and we're so thankful we did! We literally checked into Manuel's place hours after booking it for the month, and he was as responsive the whole trip.
The apartment is quite spacious, and feels even more so thanks to the towering high ceilings with gorgeous moldings. Also loved the beautiful hardwood floors, modern and clean bathrooms and kitchen, and an overall minimalist aesthetic that I found really pleasing. The orange tree in the courtyard off the living room is picture-perfect.
It's one story up with no elevator, which was not a problem for us. Just something to note with luggage or stroller, etc. The noise from neighbors could be a little frustrating at times. I'm pretty sure the man who lives upstairs and his dog are up at all hours (though both very nice).
About a 7-8 minute walk to metro. 25 minutes or so to Rossio Square. Market on both corners of street.
Overall we were very pleased. Were we to return I think we would look a little closer to Chiado, but the apartment itself was great.