This apartment was clean, stylish, and perfectly comfortable. The kitchen was well-appointed and all the amenities we could have asked for were provided. The bathroom is big, light, and clean, and the sofa/lounge area was really comfy after our long days exploring the city.
The balcony overlooks some building works in the area (and doesn't have the most beautiful view...) so that was a bit noisy when we were sitting out there with a coffee in the morning, but the excellent windows kept the noise out so we had no problems with that when we were inside. It also gets lots of lovely sun in the afternoon/evening.
The location was great and we could easily walk to everything (there's also a supermarket close by for morning pastries/whatever else). The views while walking down the hill into town were stunning.
Check-in was easy in the end - we just needed a code to enter the building which the hosts helpfully provided via Whatsapp when we arrived.
All-in-all an excellent stay, and we'd thoroughly recommend this apartment to anybody visiting the beautiful city of Porto.