I recommend Pedro's place a lot.
Its location is just perfect to discover Lisbon on foot. Besides arrival and departure I never used public transport, so, I can't tell much about it. However, the Praça Marquês de Pombal is quite near, where you'll find bus and metro stations.
The apartment is very nice and clean and I really felt at home during my time there.
You can have a good coffee to start your day with and use the well equipped kitchen to its full extent. (Which I didn't, though, as Lisbon's restaurants hardly leave any wish for that account.) Having two bathrooms is also pretty handy when there are other guests around - no long waiting to go to the toilet or to take a shower in the morning. The bed was the most comfortable one I ever had with an airbnb booking.
Pedro is a very nice guy, easy to get along with and always open to a nice chat. He was quite helpful - gave me some good hints where to eat. When my flight was cancelled he agreed for me to stay there another two days; my saviour so to speak ;)