The place is pretty modern. The location is very good and provides access to almost everything you want to see in Porto by walking. The ceilings are high and gives a nice airy feel. The amazing location comes with the downside that it gets noisy and if you leave windows open it can be loud at night. The building has elevator but please note you do have to climb a flight of steps to get to the elevator (it is stated in the description but I wanted to highlight that).
The bedroom is a bit on the smaller side and there is no laundry facilities in the unit and I believe there is no airconditioning as well. It was fine if you leave windows open but can get stuffy if the windows are closed. The water heater is small and is therefore set at a very high temperature. That makes it unsafe for kids as they can get burnt if they turn the hot water or accidentally change what you set for them when they are showering. My only other quibble is that the sofa bed in the living room isn't very comfortable but that tends to be true for sofa beds so I wouldn't recommend it for more than a couple if you are looking for a significantly longer stay.
Overall the place is in a very nice location and is very convenient for exploring Porto. Christine has done a fantastic job with the unit given the space constraints in such a historic city like Porto.