Wonderful stay in the apartment. Great patio and deck with views of the Douro river as advertised. As others have noted, this is more accurately described as a studio with screened sleeping area, or in US terms a "junior" 1 bedroom. Works well as efficiency unit and certainly large enough for 2 persons. With so much good food in Porto, tho, we did not cook in, but did stock up on basics for the fridge from the supermarket at the bottom of the hill.
The stairs and cobblestone streets up and down the hill to the main road can should be considered for those with mobility issues, but otherwise this is not really an issue. A couple minutes walk to grab the bus to town (about a 5 minute ride) but quite easy to walk into town in 20 minutes.
Marcos was an engaged and informative host. He answered all of our questions and made sure we understood the information he provided regarding transport etc. He did have to guide our Uber driver in because, as he told us, despite numerous attempts to correct the issue, Google maps does not direct autos to the apartment correctly.
Marcos is a vintner. I recommend you buy some of his wines. He can explain what he is doing and how it differs from standard wines of the Douro region.
Last comment. The property has I think 5 units. If this one is unavailable (it evidently pops up in ABnB searches at the top) then definitely check out the other apartments.