Tiago and Susana's place is beautiful and was perfect for just a few nights in Lisbon. We were centrally located (I don't think the location could've been better ), comfortable (we were two friends who each had our own bedroom/bathroom) and very clean. The view outside the balconies is very special.
A couple things to note are: 1) The stairs leading up to the apartment from Rua de S. Paolo are abundant.. we are from NYC and in decent shape so it wasn't a problem, but we saw (and heard) some people struggle. 2) The apartment is quite silent. A few times, some very drunk people outside woke me up in the middle of the night. If you're noise sensitive, you could take the windowless bedroom, or bring a small white noise machine.
Those points aside, I would definitely recommend this place for a couple friends or small group!