This is an ideal place for a couple with one or 2 small kids, big enough, 2 separate bedrooms, fully equipped kitchen, washing machine and a garden with enough shade.
We loved the attention for the little guests, there are plenty of toys and a baby cot was also supplied so that was ideal.
During our stay communication with Gabriela was also easy and quick
Finally in our view the location was also very good actually. it's about a 2 km walk to the start of the historical centre, so thats ok. I do advise to bring a carrier for your kids since Porto is really hilly. We liked to walk into the centre via rua de cedofeita, then have coffee at Base, and then continue in the old centre.
other tips: the metro station is a 10 minute walk, the bus stop however is literally around the corner and is also a quick and cheap way of transport. taxis are also very affordable (about 6€ one way).
also for families with kids, the palace gardens park is nice and also less than 10 minutes by foot
I can think of one small downside of this apartment and that is that the place heats up real fast and the heat lingers at night
All in all we had a great time at Casa da Paz and wouldn't hesitate to come back next time around