My wife and I stayed here on our first visit to Lisbon. It was only about a 15-20 minute ride from the airport to the apartment and the apartment is in a great location. The apartment is wonderful and in a super accessible location. We were able to walk just about anywhere we wanted and felt very safe doing so.
Antonio had some great suggestions as well for things to do in the city. We were only staying for 3 nights so we couldn't get to all of the suggestions, but the ones we did were fabulous.
Definitely go visit Lisbon, it's a remarkable city, and stay here for a convenient and comfortable stay. Thank you!