The good things - the apartment is very centrally located and it's so easy to get to the most popular areas in Lisbon. It's also really brightly decorated.
1. Noise - the noise in the area that seeps into the apartment is unbearable. Unless you are a deep sleeper who can sleep through cars honking and motorcycles speeding, you will not get any rest. Even within the apartment, the floorboards are inexplicably noisy. Each step makes more noise than the last and when someone walks in the hallway you WILL wake up.
2. Accuracy and honesty - the apartment is much smaller than it looks in pictures. It's more of a studio apartment. There is an adjoining bunk bed room but it's tiny. We only stuffed our luggage in there. Also, we weren't warned of the works that were taking place in the building that they were aware of beforehand - it was the neighbours who told us about this (they weren't warned either and when they confronted the host days before our arrival, he claimed not to know about it)
3. Limited amenities - don't expect an iron or bottled water
Unfortunately, for us the bad outweighed the good.