The aparment is amazing!
It feels very spacious and has everything you could need for a few days' stay, yet it is minimal and stylish.
As many others, I checked-in in the office. The staff was very nice and I was advised to download their app. I gotta admit, it was somewhat helpful (explaining how to use equipment at house etc.) but was often crashing. I was told it was only released last month, so I imagine it's still worked on.
FInding the apartment was a bit tricky for me, but that's cause I was looking at the wrong side of the street at first! Note that the google maps isn't showing the exact adress location, so you might have to do a little bit of searching for the right door.
When we entered it was very clean; a bottle of wine waiting for us, which was a nice touch. Uncovered windows let a lot of light in, and if you lean out of them a bit, you will be able to see a bit of the Ponte Luís bridge. If you happen to be us unlucky as we were, and come during, possibly, the most rainy days ever, there are heaters. The place can get quite chilly if you don't use them, but it's very nice if you do. There were also Netflix and Youtube apps on the TV, and some playing cards inside, so it's lovely even if you have to stay in for a while and can't enjoy the views outside.
Location is perfect, literally five minutes walk away from the Douro river and maybe ten away from the São Bento train station. There are a lot of touristy shops everywhere around and loads of food serving places. Personal favourite was Taberna Dos Mercadores, which is a little rustic restaurant litterally couple minutes down the street from the apartament, serving authenthic and just heavenly food for a very reasonable price.
Overall, it's a great place and I couldn't recommend staying there more. I feel like the price is very reasonable for a nice little apartament like that. I hope to be coming back one day!