The apartment looks new, clean and is very nicely designed.
We had a comfortable stay but there are a few remarks.
There's construction across the street. We didn't experience too much noise and the windows are good at shutting the noise out.
We had the corner apartment right next to the Praça do Comércio arched gate. There was music coming from there in the evening. It was enjoyable for us but might not be for you.
The door is very difficult to figure out if it's the first time you encounter the lock that they're using. You might have encountered it at another hotel or apartment and it won't be an issue, but if you haven't, be prepared to waste time trying to figure it out. Our nextdoor neighbors had the same experience saying it took them a day to figure this lock out.
This brings me to the cell reception, a least on the MEO network. We had to go to the other end of the hall to get enough reception to send messages to the owners so that they'd help us to open the door.
Finally, having more hand towels would've been great, for example one for the kitchen. And while they have a Krups "espresso" capsule machine, they don't actually give you capsules to use, and while they have a clothes washing machine they don't give you detergent.