Gabriel is very nice and was very welcoming. The flat isn't huge, but has a great location. Everything was great except for two minor concerns:
1) the area around the flat can be a bit noisy until 2am or so because there are so many parties--if you're coming to Lisbon for the parties, this is probably a plus, as the flat has a great location.
2) the website says three beds are available. This is not really the case. There's a double bed, a smallish sofa (that does not pull out) and two single air mattresses that are acceptable but not at all great. We were surprised by this, so just be aware and make sure the flat is right for your group.