I was very happy with my stay at Paulo + Christine's place. Teresa was very quick to respond when I had some initial trouble finding the place and I found the place right away, and all of them were very good with communication throughout my stay. Only thing I'd say is the stairs are pretty steep, so may not be suitable for someone who's differently abled or carrying heavy luggage.
The place itself is super cute, though, and in a really central location. I was even able to do my laundry, which was great. I wish I had stayed longer and actually explored the neighborhood a bit more since there were so many awesome eateries and stores around. I would recommend this apartment to anyone considering a vacation in beautiful Lisbon!