Our experience at this apartment seems somewhat different to most going by previous reviews, so hopefully others don't encounter the same sorts of things we did.
Some other reviewers have already mentioned the rubbish left outside by nearby restaurants at the end of the night, but it seems during our stay that the rubbish was dropped off as noisily and with as much yelling as they could possibly manage. This continued on for some time - not exactly ideal at 1AM when you're trying to get some sleep after a big day around Lisbon.
The apartment itself was okay - spacious and well furnished given the location but very dark with only one small window (photos are quite misleading) and a strong mildew smell. Likely the apartment doesn't get enough ventilation. What topped it off though was the random scratching noises in the roof that would start at all times during the night and morning. We never figured out what was causing it but was so disturbing as to wake as up when it started happening.
It's a shame the apartment wasn't up to scratch because Ulrik was a friendly and communicative host, providing tips for the area, detailed maps and sending us very clear instructions to get to the place, given its tricky location. We can't also fault the location, smack bang in the middle of the action in Alfama.