My family, including 2 young children and my in-laws, visited Lisbon and stayed at Joao's place. His place was perfect for us and I couldn't recommend it any higher.
The location was great. The old town charm of the neighborhood was apparent during the day and very active in the nighttime. Yes, there is some street noise but with good windows it wasn't a bother to us- and note that we did have 2 young kids we desperately wanted to sleep, and they did.
The space was perfect for our family unit. It was so nice to have individual rooms for our kids and the adults. And the public area kitchen and family room was great for socializing while getting ready in the morning or winding down at night.
Finally, Joao was the most accommodating and helpful host we have ever stayed with. He was always available and helped with airport transfers and dinner reservations, etc.
We had a great experience in Lisbon and I highly recommend staying at Joao's place. If it is available please book it immediately!!