We spent a weekend in the flat, which is exactly as beautiful as it looks in the pictures! We didn't meet the owners but communication was great and any questions were answered very promptly. Lots of information about good places to eat, go for a drink and nearby shops was available in the flat- very helpful!
The flat itself was very safe and comfortable, and spacious for three people sharing it. It felt very homely, and we loved the huge sofa - great for a rest at the end of the day.
The location was great too, very close to all the main sights of Porto but in a quiet street so there was no noise at night.
We'd definitely recommend it to anyone looking for a place to stay when visiting the city.